It's hard to say for me because I cast during the winter and stock up with several thousands and end up casting in the summer also.
I guess I could take an average of 70 + rounds per pound of powder I shoot up in a year.
Last year I was way below what I used in the past with under four cases, year before I used over 5 cases.
With the price of lead and tin being what it is now I shoot into one spot of the berm so I can recycle my lead as much as I can and re use it. I just recycled a 5 gallon bucket full I collected last year.
Kurt