-66.3% is the change from 638 to 215
Calculation steps:
[( 215 - 638 ) ÷ 638] x 100 = -66.3%
Formula
Percentage change = [(215 - 638) / 638] x 100
Subtract the new number by the original number
215 - 638 = -423
-423 ÷ 638 = -0.6630094043887147
-0.6630094043887147 x 100 = -66.3%