-92.07% is the change from 643 to 51
Calculation steps:
[( 51 - 643 ) ÷ 643] x 100 = -92.07%
Formula
Percentage change = [(51 - 643) / 643] x 100
Subtract the new number by the original number
51 - 643 = -592
-592 ÷ 643 = -0.9206842923794712
-0.9206842923794712 x 100 = -92.07%