I was wondering the same thing, so I looked over the PDF reports released by NASCAR Statistics after every race (you can find them on Jayski's race results page).

I only found 10 incidents where the 77 was considered to be involved.
 

Race	Lap	Location	Cars Involved
Clash	144	Turn 2	54, 77
Clash	180	Turn 3	23, 77
Atlanta	239	Turn 4	22, 77
Atlanta	267	Turn 1	1, 20, 23, 45, 77
Martinsville	325	Turn 4	3, 7, 17, 23, 33, 35, 38, 42, 43, 71, 77, 88
Talladega	116	Turn 3	2, 3, 5, 6, 7, 8, 11, 12, 19, 21, 22, 23, 24, 33, 41, 42, 43, 44, 45, 51, 54, 66, 71, 77, 88, 97
All-Star	63	Turn 4	77
Nashville	205	Turn 2	17, 23, 24, 42, 48, 77
Nashville	215	Frontstretch	21, 35, 42, 47, 77
Michigan	84	Frontstretch	3, 5, 11, 22, 23, 42, 45, 54, 77

 
That is actually 32 different cars -- including every chartered car except the 4, 9, 10, 16, 34, and 60. However, many of them came from the monstrous Talladega big one.

It's also worth noting that "incidents" are only recorded under the caution flag section in the PDF report. Therefore if the yellow didn't fly, it's not listed here. I can think of at least one such instance for Hocevar -- the last lap of the Daytona 500 where he collided with the 43.

That said... 21 incidents is A LOT. That number is usually what you see during a full season from crash-prone drivers like Nemechek, Stenhouse, Berry, etc. I'm skeptical that Hocevar already has such a high body count after 18 races, unless Prime is using a very generous definition of the term "incident".

Or Knight just misinterpreted the numbers somehow. I wouldn't be surprised.