Most of us probably don't have a clue. These days, I leave my gps on whenever I'm on the boat and that gives an annual tally. But I don't keep any written records of it. I know last season we did about 1500 nm. The season before, I vaguely recall about 2000nm. Average since we've been in Maine is probably under 1000nm, range.
I'd say moving to this area of the coast, we greatly increased our miles over Lake Champlain in season(sailing grounds could have a huge effect on seasonal miles local boats sail).
I'd also say when we went from a 28' to a 38' boat we greatly increased our miles(maybe doubled) in season. This could be personal to our family of four. The larger boat moves faster but we simply found it more enjoyable to sail longer on the larger boat.
I'd also guess that when we cruised over the winter a couple of times in the past(with the smaller boat), we of course did the most miles. But we also covered the least portion of those miles under sail.