When should you fold a set with no flush or straight possible?

Last night at the same table I lost to set vs set twice when set vs set is suppose to happen 1 out of 100 times.

So I went back for the last couple of weeks to look at the odds.

Do you ever fold a set when there is no flush or straight possible on the board?

In the last couple weeks in pokerroom

AA - set 5 times
KK - set 8 times
QQ - set 10 times -> Lost Set vs Set
JJ - set 6 times
1010 - set 1 times
99 - set 13 times
88 - set 4 times -> Won Set vs Set
77 - set 8 times
66 - set 7 times
55 - set 11 times
44 - set 6 times
33 - set 5 times -> Lost Set vs Set
22 - set 6 times

set vs set 3 times out of 90. Maybe just lucky?