Does TT want average or the total of the three prior yrs for Box 17 on K1 for AC - Gross Receipts for section 448(c)? My K1 says STMT - statement has 3 yrs listed out

According to the instructions for filling out Form 8990 Limitation on Business Interest Expense listed here, the amount that would go into this box is the average of the prior three years annual Gross Receipts. To determine the entry, it states you must.

1. Add the gross receipts for the 3 prior tax years, and
2. Dividing the total by 3.