-85.09% is the change from 342 to 51
Calculation steps:
[( 51 - 342 ) ÷ 342] x 100 = -85.09%
Formula
Percentage change = [(51 - 342) / 342] x 100
Subtract the new number by the original number
51 - 342 = -291
-291 ÷ 342 = -0.8508771929824561
-0.8508771929824561 x 100 = -85.09%