GMT, I think your question pertains to a masters state championship TT event and why the pre-registration is low. This year promoters of NorCal races complained of low pre-registration and several races were canceled due to projected losses if the race were held.
Our championships events at both road and track have had lower turnout and pre-registration this year. I think a lot of this is racers trying to handicap their chances of getting on the podium based on who enters and waiting to the last moment. If they do not think they can podium, they do not enter.
With respect to demographics, we see about the same breakdown in championship events with lower turnout in the 30 to 34 and 35 to 39 age categories. Some of the best ITT times come out of the 40 to 55 age demographic.
For general racing, the largest fields are the 45+ 1,2,3,4 which seem to always fill up with 100 racers.