Proper preparation for the trip is one of the best ways to keep from being a statistic.  The following information is not meant to be a "scare tactic", but to show you the importance of proper preparation and common sense. I [John Combs] have hiked the Grand Canyon four times and know that it is perfectly safe as long as you are adequately prepared.

EMS Statistics for 1997
Total number of EMS incidents 1376
Advanced Life Support Cases 274
Advanced Cardiac Life Support 96
Basic Life Support 605
Minor Medical Cases 396

Environmental Emergencies:
Heat Exhaustion143
Hyponatremia 29
Heat Stroke 0

Fatalities: 22 (includes Grand Canyon Village and Tusayan)
Falls 2
Natural 8
Suicide 3
MVA 2
Plane Crash 2
Drowning 4
Other 1

Transportation:
Ambulance Transport 325
Helicopter 224
Fixed Wing 4
Mule Evacuations 7
Hiker Assists/Walkouts 354

Quoted from Grand Canyon Ranger Chuck's Website:
I believe that there have been 8 deaths this year [1996], 3 to 4 are heat related.  1 did jump, other illness, like cardiac.

This summer is very strange - record number of calls for SARS [Search and Rescues] so far. 250 that we have responded to. Things like:

7/23 [July 23, 1996] : Report of overdue hiker, in Nankoweap area, work to 12:30 [am] at night then up at 4:30 [am] in the morning to fly personnel in to walk the trails and beaches to find the guy. At 10:30 [am] we find him. Flying the people back, and by 1:00 [pm] everyone is back. The guy looses his pack over the ledge. In the process of getting  together technical rescue equipment to get the pack when we get call at Phantom Ranch - 10 year old male with CPR in progress. Fly in on a young male that has heat stroke. Fly him to the clinic, full ACLS in progress to try and save the boy. At the clinic he dies, and another call heat stroke on the South Kaibab trail, again we go. We fly out another person 52 yo [year-old] female with heat stroke.  She almost dies, but we save her. 2 more requests for help on South Kaibab trail. (day time temps 114) - We are going non-stop from 5:00 am to 9:30 pm. Then to debriefings for the death.
 

1996 - 250 rescues, 8 fatalities (1 did jump, other illness, like cardiac)
1995 - 380 rescues, 23 fatalities, 66 total EMS personnel; 1305 total responses, including medical calls, searches, and rescues
1994 - 474 rescues, 11 fatalities
1993- 404 rescues, unknown fatalities; Reason 1995 SARs were down was due to the closure of main; trails due to washouts for most of the year.

Most of the Search and Rescue calls are for day hikers.

Bits and Pieces from May/June 2000
On May 25th, rangers received a report that 61-year-old John O'Donnell had failed to return from a day hike in the canyon. His cousin advised that he planned on hiking down the South Kaibab trail, across the Tonto trail , and back up the Bright Angel trail.  O'Donnell had only two small water bottles, no food, no flashlight, no map and no extra clothing.  Temperatures in the canyon that day ranged from 111 degrees during the day to 102 degrees at night. Rangers established containment points at the South Kaibab and Bright Angel trailheads and swept the three trails. No sign of O'Donnell was found.  An aerial search ensued on the following morning, but initial efforts were fruitless. Rangers familiar with the history of lost people in this area made a second flight of the area and this time spotted O'Donnell. He was found to be suffering from severe dehydration and was hallucinating. He had also been hiding from searchers, who he thought were "bad guys." O'Donnell had water in one of his bottles, but told rangers he hadn't drunk it because a man sitting next to him said it was bad water (O'Donnell was found alone). He was flown out and treated at a local medical facility. Doctors said that he would not have survived another day if he hadn't been found.

Just before dawn on May 28th, a visitor Mike fell 40 feet while trying to retrieve his camera, which had fallen over the edge near the Cape Royal scenic overlook on the North Rim. Rangers rappelled to the man, secured him so he wouldn't fall any further, and provided advanced life support. He was evacuated by helicopter short-haul, lowered to the Cape Royal parking lot, then taken by private air ambulance to Flagstaff Medical Center, where he was admitted with internal injuries and rib fractures.

May 24, a group of sixteen, from Lehigh University in Pennsylvania, had attempted a round-trip day-hike to the Colorado River on the Lava Falls Trail. Though short, this trail is extremely steep, difficult, and exposed. With yesterday's temperatures exceeding 108 degrees Fahrenheit, only six of the sixteen hikers had returned by nightfall. At 6:40 p.m. a park visitor used an emergency phone at the Tuweap Ranger Station to report the missing hikers. Three helicopters were dispatched to the scene, but were forced to postpone flights into the canyon due to weather and ensuing darkness. SAR personnel conducted a "hasty search" along the rugged trail after dark. At 11:00 p.m. they located one more hiker from the group, who reported that his remaining (nine) companions were further down in the canyon and near the river, where they intended to spend the rest of the night. At first light this morning, the DPS helicopter located and evacuated all nine from the canyon. One hiker, suffering a leg injury, was flown to the Flagstaff Medical Center. National Park Service Ranger Jeff Martinelli reported that all of the other fifteen hikers were medically evaluated; most were recovering from mild to moderately serious levels of dehydration.  Heat was considered a factor, with temperatures in the triple digits, and they were just unprepared for such a steep and rough trail (1.5 mile).  Mohave County sheriff's spokesman Steve Johnson said the eight were members of a student and faculty leadership group from Lehigh University in Bethlehem, Penn. The lost hikers became separated from 12 other group members Wednesday and were found in the area of the Lava Falls Trail along the Colorado River.

June 03 - A Belgian backpacker died Friday during a hike in the inner backcountry section of the Grand Canyon. The man had been hiking the Tonto Trail with three companions from Belgium on a planned three day trip when he began havingproblems. The other backpackers hiked to the Colorado River and asked a commercial rafting group to ask forhelp about 4:30 p.m.  Park officials said rangers arrived by helicopter in 17 minutes and declared the man dead at the scene. His body was evacuated to the Coconino County Medical Examiners Office for investigation. The other backpackers told rangers they had difficulty locating water and changed their itinerary to make trips to the Colorado River for water. The Tonto Trail traverses a large plateau about 2000 feet above the river on the south wall of the canyon.