Slowly declining fuel mileage

[Rockosmith]

My '04 1150R seems to be returning somewhat less fuel mileage as it ages. Early in its life it consistently returned 47+ mpg with a few instances of 53 mpg. Now, with 92000 miles, it is averaging 45mpg. I don't think my riding style has changed. Could it be the almost universal alcohol in the gas that may not have been there many thousand miles ago?? Could the oxygen sensor be tired?? I know this isn't much of a change, but it is a trend and I am curious. Thoughts??

Thanks

[Sunbeemer]

Alcohol does decrease fuel mileage. I've heard estimates from 8-12%, which is in your ballpark.
Having any driveability issues that would suggest an O2 sensor problem?
Burning more oil than usual?
You could check cylinder compression to rule out worn piston rings and valves.

[Rockosmith]

No driveability issues at all. Oil usage is very slight, don't need to add between changes. Probably alcohol and winter blend.