-66.78% is the change from 921 to 306
Calculation steps:
[( 306 - 921 ) ÷ 921] x 100 = -66.78%
Formula
Percentage change = [(306 - 921) / 921] x 100
Subtract the new number by the original number
306 - 921 = -615
-615 ÷ 921 = -0.6677524429967426
-0.6677524429967426 x 100 = -66.78%