How can you date your mercury 2.2 outboard?

Mercury 2.2 HP 1 Cylinder Outboards manufactured in the USA from 1984 to 1989 may be dated from the serial number: Year SN Begins Year 1984 8075603 1985 8087123 1986 A800761 1987 A805221 1988 A817421 1989 A837101 (There might be a "0" in front of the "A".)