Does that even matter? US GDP is orders of magnitude larger than Iran. The American way of war has long been based on minimizing casualties through overwhelming materiel superiority and profligate ammunition expenditure. Back in WWII the USA literally out produced Japan by 1000:1 in some types of munitions. Our industrial base has decayed a bit lately but that's a fixable problem.
It matters in so far as the production rate for e.g. air defense interceptors is much lower than the rate at which they've been used in the Iran war. Which is probably one of the reasons the US was ready for a ceasefire.
They might have enough stockpiles to continue this war for a while, but it thins out the capabilities in other theaters, making the US generally more vulnerable.
800 Patriot missiles were used within the first 3 days in the Iran war. This is greater than the total number of Patriot missiles received by Ukraine during the entire war with Russia.
The USA is rapidly depleting it's missile stocks, and the Orange president is displaying some funny priorities.
how much ammunition did the US navy use to shoot down incoming drones, and what are the cost of those vs the attacker's cost?