-21.43% is the change from 70 to 55
Calculation steps:
[( 55 - 70 ) ÷ 70] x 100 = -21.43%
Formula
Percentage change = [(55 - 70) / 70] x 100
Subtract the new number by the original number
55 - 70 = -15
-15 ÷ 70 = -0.21428571428571427
-0.21428571428571427 x 100 = -21.43%