-79.7% is the change from 670 to 136
Calculation steps:
[( 136 - 670 ) ÷ 670] x 100 = -79.7%
Formula
Percentage change = [(136 - 670) / 670] x 100
Subtract the new number by the original number
136 - 670 = -534
-534 ÷ 670 = -0.7970149253731343
-0.7970149253731343 x 100 = -79.7%