-69.4% is the change from 915 to 280
Calculation steps:
[( 280 - 915 ) ÷ 915] x 100 = -69.4%
Formula
Percentage change = [(280 - 915) / 915] x 100
Subtract the new number by the original number
280 - 915 = -635
-635 ÷ 915 = -0.6939890710382514
-0.6939890710382514 x 100 = -69.4%