-49.02% is the change from 510 to 260
Calculation steps:
[( 260 - 510 ) ÷ 510] x 100 = -49.02%
Formula
Percentage change = [(260 - 510) / 510] x 100
Subtract the new number by the original number
260 - 510 = -250
-250 ÷ 510 = -0.49019607843137253
-0.49019607843137253 x 100 = -49.02%