My riding is all over the map, as well. When I first got Betty I was just making my business tick. Then my wife had surgery. Then things picked up. Then she blew her knee out and had more surgery.
But I found some old inheritance money, they invented the 48, and now I had a 'scooter' to do quick, short, cheap rides I could squeeze in anywhere, and anytime.
Wisconsin has roughly a six month riding season. If my average is reflected like the last two years, I'll do +8K as a total for the two bikes per season. With an average taken over the last ten years, it would drop.
How that figures over +40 years, I have no idea.