-76.5% is the change from 217 to 51
Calculation steps:
[( 51 - 217 ) ÷ 217] x 100 = -76.5%
Formula
Percentage change = [(51 - 217) / 217] x 100
Subtract the new number by the original number
51 - 217 = -166
-166 ÷ 217 = -0.7649769585253456
-0.7649769585253456 x 100 = -76.5%