-6.43% is the change from 311 to 291
Calculation steps:
[( 291 - 311 ) ÷ 311] x 100 = -6.43%
Formula
Percentage change = [(291 - 311) / 311] x 100
Subtract the new number by the original number
291 - 311 = -20
-20 ÷ 311 = -0.06430868167202572
-0.06430868167202572 x 100 = -6.43%