Assuming the interest is compounded monthly, which must be verified, it would be $4,000 per month. Note that the principal will rise every month if the interest is not withdrawn.
It's 4% a month (100,000 x 1.04 - 100,000 = 4000). If you want to know how much it is converted to annual interest, than it is (1.04^12 - 1) x 100% a year (equals ~60.1% a year)
