Primes are strong pseudoprimes with respect to all bases

TableForm[Table[{b, PowerMod[b,3,13], PowerMod[b,6,13], PowerMod[b, 12, 13]},{b, 1, 12}]]

TableForm[Table[{b, PowerMod[b,5,41], PowerMod[b,10,41], PowerMod[b, 20, 41], PowerMod[b, 40, 41]},{b, 1, 40}]]

Challenge

Find all strong witnesses to the primality of (a) n=65 and (b) n=91, and check that these account for less than a quarter of all the bases relatively prime to n in the range 1<b<n-1.