-50.1% is the change from 521 to 260
Calculation steps:
[( 260 - 521 ) ÷ 521] x 100 = -50.1%
Formula
Percentage change = [(260 - 521) / 521] x 100
Subtract the new number by the original number
260 - 521 = -261
-261 ÷ 521 = -0.5009596928982726
-0.5009596928982726 x 100 = -50.1%