If it's anything like the sport of bicycling in the USA, for a long time it's been a sport of caucasians, this is changing a bit but it trickles all the way up just from a sampling of who represents the USA at the Olympics and World Championships. Possibly a combination of the high cost of entry with the clique-ishness and the sport requiring quite a bit of free time and the support or money to have that much free time. Not talking about kids riding around the neighborhood but people who continue or start riding as adults, so not a social shift at all but existing demographics.