-1.94% is the change from 515 to 505
Calculation steps:
[( 505 - 515 ) ÷ 515] x 100 = -1.94%
Formula
Percentage change = [(505 - 515) / 515] x 100
Subtract the new number by the original number
505 - 515 = -10
-10 ÷ 515 = -0.019417475728155338
-0.019417475728155338 x 100 = -1.94%