There is the joke that mathematicians only know 0, 1, and 2 (since higher numbers are rarely used in higher mathematics, contrary to the believe that mathematics is just arithmetic), and it's at least somewhat true for me (data are from all my lecture transcripts of my first two and a half semesters studying mathematics):
Digit: Total number Percentage
0: 7457 20.017 %
1: 11560 31.030 %
2: 10049 26.974 %
3: 3207 8.608 %
4: 1371 3.680 %
5: 976 2.620 %
6: 901 2.419 %
7: 547 1.468 %
8: 605 1.624 %
9: 581 1.560 %