Another variable to consider is ethenol fuel as opposed to straight 100% gas. Ethenol is cheap gas, but ruins my mpg, by as much as 20%. I'll go out of my way not to use it if I can. Sometimes you can't help but to fill up with it, but I avoid ethanol when I can.
KTM 1190 ADVenture R (the best one yet!)
KTM 525 EXC plated