By the Numbers: Boston Marathon bombings

(CNN) -- On Patriots' Day, a state holiday in Massachusetts, an unidentified person or group detonated two bombs near the finish line at the Boston Marathon. Here are some important numbers relating to the tragedy and its aftermath.

2:45pm - Time of the first explosion.

3 - Number of people who were killed.

At least 174 - People who were injured and treated at area hospitals.

12 seconds - Length of time in between the two bomb blasts.

50 to 100 yards - Distance between the placement of the two bombs.

$50,000 - Amount of the reward for information leading to the arrest and conviction of those responsible for the attack.

2 - Number of devices found by law enforcement. Each bomb was reportedly placed in a pressure cooker, then hidden in a backpack.

12 blocks - Area of the crime scene, after being reduced from 15.

3 - Boston pro sports events canceled or postponed in light of Monday's events: Fenway Park baseball stadium open house, postponed; Boston Bruins hockey game, postponed; Boston Celtics basketball game, canceled.

26,839 - Entrants in this year's Boston Marathon.

23,336 - Runners who started.

75.3 - Percentage who finished.

5,756 - Runners who were unable to finish the race.

2:10:22 - Race time of the men's winner, Lelisa Desisa of Ethiopia.

2:26:25 - Race time of the women's winner, Rita Jeptoo of Kenya.

617,594 - Population of Boston, according to the 2010 U.S. Census.

117 - Number of times the Boston Marathon has been held.

570 - Number of marathons held annually in the United States, as of September 2012.