89. The state of Washington encodes the last two digits of the year of birth into driver’s license numbers (in positions 8 and 9) by subtracting the two-digit number from 100. For example, a person born in 1942 has 58 in positions 8 and 9, whereas a person born in 1971 has 29 in positions 8 and 9. Speculate on the reason for subtracting the birth year from 100.
89.
Since many people do not like to make their age public, this method is used to make it less likely that people would notice that the license number encodes year of birth.