-92.86% is the change from 210 to 15
Calculation steps:
[( 15 - 210 ) ÷ 210] x 100 = -92.86%
Formula
Percentage change = [(15 - 210) / 210] x 100
Subtract the new number by the original number
15 - 210 = -195
-195 ÷ 210 = -0.9285714285714286
-0.9285714285714286 x 100 = -92.86%