Grand Canyon Day HIke for 4 and 6 years old girls

It took about 5+ hours to walk down to Colorado River from the South Rim on Bright Angel Trail, It was moderate 90-95F on this May 3, 2009 day hear.After about 1 hour of rest it would take another 7+ hour to get back up to the trailhead, making 15.5 miles hike in 13 1/3 hours. About 27-30 adults hiked Grand Canyon as day hike on this day. ( I asked almost every hiker) The only other child on a trail who made the similar ( 1 mile longer) hike this day was 9 year old boy from Prague, Czech Republic. Rather impressive coincidence on this day that all 3 grand canyon day hikers younger than 14 or 15 years old are born with 600 miles from each other in ex- soviet bloc countries, about 7000 miles from Grand Canyon . It is interesting what percentage of Grand Canyon visitors are born in Eastern Europe? 0.2 % or 0.3% What would you guess?