EXCEL IF statement with %

Hello,
Im trying to get a formula for the following statment:

A1 is Within 20% of net sales, then give it a score of 5
A1 bt. 21-25% of net sales, then give it a score of 4
A1 is bt. 26-30% of net sales, then give it a score of 3
A1 is bt. 31-35% of net sales, then give it a score of 2
A1 is More than 36% of net sales, then give it a score of 1

Also, what's the forecast accuracy formula if,
Final Sales is -22,799 but I forecasted $89,118. The Variance is -111,917. How do you calculate the forecast accuracy?