-49.9% is the change from 517 to 259
Calculation steps:
[( 259 - 517 ) ÷ 517] x 100 = -49.9%
Formula
Percentage change = [(259 - 517) / 517] x 100
Subtract the new number by the original number
259 - 517 = -258
-258 ÷ 517 = -0.4990328820116054
-0.4990328820116054 x 100 = -49.9%