Forever six-year-old Calvin and his furry pal Hobbes put Calvin’s parents through a whole hell of a lot in the decade they appeared in Bill Watterson’s iconic comic strips.

But just how much money did Calvin—who was prone to a legendary amount of mostly well-meaning mischief—cost the folks?

The duo racked up nearly $16,000 in damage from 1985 to 1995, which comes out to almost $1,900 annually, according to Matt Michel, editor of the Proceedings of the Natural Institute of Science, a satirical (though kind of accurate) scientific journal.

Michel read through the entire “Calvin and Hobbes” published works and documented all instances of damage inflicted by the mischievous duo, then estimated costs assuming Calvin lived in Chagrin Falls, Ohio, where Watterson lived for a long time. You can read Michel’s complete findings here.

PNIS

PNIS