-80.7% is the change from 342 to 66
Calculation steps:
[( 66 - 342 ) ÷ 342] x 100 = -80.7%
Formula
Percentage change = [(66 - 342) / 342] x 100
Subtract the new number by the original number
66 - 342 = -276
-276 ÷ 342 = -0.8070175438596491
-0.8070175438596491 x 100 = -80.7%