It's pretty much impossible to know the answer to the OP's question without asking every individual shooter.
But to put some perspective on the accomplishment, out of 167,405 100-target singles registered in 2011, there were 3,705 100x100s, or 2.21%. The most common score was 96 (12,970).
Out of 45,368 200-target singles registered, there were 350 200x200 (0.77%). The most common score in a 200-target event was 194 (2,331).
There are probably a few more 100 straights and 200 hundred straights than I've indicated because there are some marathon targets that are entered in as a total out of 300, 400, 500, 600, 700 or 800. But the individual scores aren't broken out.
In handicap, there were 69 100 straights registered out of 200,234 (0.03%). The most common 100-target handicap score was 89 (13,173).
In doubles, there were 289 100 straights registered out of 106,559 (0.27%). The most common 100-target doubles score was 89 (5,176).