-67.96% is the change from 309 to 99
Calculation steps:
[( 99 - 309 ) ÷ 309] x 100 = -67.96%
Formula
Percentage change = [(99 - 309) / 309] x 100
Subtract the new number by the original number
99 - 309 = -210
-210 ÷ 309 = -0.6796116504854369
-0.6796116504854369 x 100 = -67.96%