I want to create a formula that would calculate like this...
unfortunately, i am unable to use the formula using IF as the data is too long. Any idea how i can do so?

20% 5
19% 4.75
18% 4.50
17% 4.25
16% 4.00
15% 3.75
14% 3.50
13% 3.25
12% 3.00
11% 2.75
10% 2.50
9% 2.25
8% 2.00
7% 1.75
6% 1.50
5% 1.25
4% 1.00
3% 0.75
2% 0.50
1% 0.25
0% 0.00