-92.5% is the change from 680 to 51
Calculation steps:
[( 51 - 680 ) ÷ 680] x 100 = -92.5%
Formula
Percentage change = [(51 - 680) / 680] x 100
Subtract the new number by the original number
51 - 680 = -629
-629 ÷ 680 = -0.925
-0.925 x 100 = -92.5%
Example