Why 74%?

33 is in the heart family (3, 6, 9) and 7 is in the mind family (1, 5, 7). 33 is a master number, so it is matched as its root, 6. Mind with heart starts at 74. The nudge comes from the roots: 6 + 7 = 13, which leaves 1 when divided by 3, so the nudge is 0. 74 + 0 = 74.

Out of the 78 possible pairings, 30 score higher than this one. Rarity: 0.9% of birthdays from 1950 to 2009 give 33 and 11.1% give 7, so about 1 in 517 random pairs of birthdays land on exactly this pair.

The rule is our own design, not a numerologist's chart, and numerology is not a science.