-0.22% is the change from 917 to 915
Calculation steps:
[( 915 - 917 ) ÷ 917] x 100 = -0.22%
Formula
Percentage change = [(915 - 917) / 917] x 100
Subtract the new number by the original number
915 - 917 = -2
-2 ÷ 917 = -0.0021810250817884407
-0.0021810250817884407 x 100 = -0.22%