Is your example showing results at the group level? If you want a count of records yeartodate, then you should be able to create a formula {@ytd} like:
if {table.date} in yeartodate then 1 else 0
Place this in the detail section and right click on it and insert a summary (SUM, not count) on it. Then if you want a percentage at the group level of the total yeartodate, create a formula:
sum({@ytd},{table.groupfield}) % sum({@ytd})
If you want the percentage to be of all records, change the second part of the formula to: count({table.date})
-LB