how to set the auto *(times) N% at column B, when the value of the column A.

example:

column A column B (result)
100 100 * 1%
500 500 * 5%
700 700 * 7%
200 200 * 2%
50 50 * 0%

0 - 99 = 0%
100 - 199 = 1%
200 - 299 = 2%
...