[OT] Hockey rinks in US?

Does anyone know how many hockey rinks there are in the US? Maybe this could be one of those IQ-savvy questions Microsoft asks job candidates such as how many gas stations there are in the US? (You have to know the approximate US population and then decide how many people each gas station might support.)

At 100 rinks per state, that would be 5,000. More in Minnesota, fewer in Alabama and Hawaii. At one rink per 25,000 population, that would about 12,000. So I'm guessing more than 1,000 rinks, fewer than 25,000.

Interesting also if there was a per capita comparison of hockey rinks in the US, Canada, Sweden, Germany, etcetera. One expired onlined citation, meaning Google sees it but the page isn't there, says 3,500 rinks in Canada, and if that's true, that's one for every 9,000 people (population about 32 million). That suggests that in the U.S. it'd have to be one for every 25,000 or 50,000, not one rink per 10,000 Yanks.

Interesting too (if for no other reason than I've got all my holiday presents wrapped but I'm suffering writer's block and don't want to go back to working for a bit) to compare hockey rinks to golf courses or (this is far afield) polo fields or auto race tracks or baseball fields.