-32.52% is the change from 947 to 639
Calculation steps:
[( 639 - 947 ) ÷ 947] x 100 = -32.52%
Formula
Percentage change = [(639 - 947) / 947] x 100
Subtract the new number by the original number
639 - 947 = -308
-308 ÷ 947 = -0.3252375923970433
-0.3252375923970433 x 100 = -32.52%