-29.77% is the change from 309 to 217
Calculation steps:
[( 217 - 309 ) ÷ 309] x 100 = -29.77%
Formula
Percentage change = [(217 - 309) / 309] x 100
Subtract the new number by the original number
217 - 309 = -92
-92 ÷ 309 = -0.2977346278317152
-0.2977346278317152 x 100 = -29.77%