proportion of income spent on one's dog
Jocular pun on エンゲル係数 (Engel's coefficient), replacing エン with ワン (woof) to refer to dog-related expenses.
Lately, our dog's medical bills are high, so our 'wangel coefficient' is going up.
We're spending so much on our pet that the 'wangel coefficient' might exceed the Engel coefficient.