For general elections, V means that you voted. For primaries, the letter tells which party’s primary you voted in; N either means non-partisan (it’s sometimes possible to take a non-partisan ballot to vote on referenda that are held concurrent with a primary) or perhaps Not Voting; you’d have to ask the clerk.
When there are two elections within a year, the first is the primary and the second is the general election. I suspect your first line should read 01 because there would be both a primary and a general election in 2000. The elections in odd-numbered years are local elections.