holy crap!highly dependent of actual use, i only went through 4000 pellets last year 95% of that was with a 10 meter air rifle I use to not completely loose any shooting skills.
I shoot at 20 yards and closer with a Daisy 853. Which is more than accurate enough to show your fundamentals are slacking.
I know a few guys that do the field target stuff and they are shooting 10k's a year easy. all pcp rifles and tanks.
My friends son is getting deep into 10m competitive air rifle, 2000 pellets a week or so is not hard for him to piss through.
I must go thru 100 a year