-1.05% is the change from 668 to 661
Calculation steps:
[( 661 - 668 ) ÷ 668] x 100 = -1.05%
Formula
Percentage change = [(661 - 668) / 668] x 100
Subtract the new number by the original number
661 - 668 = -7
-7 ÷ 668 = -0.010479041916167664
-0.010479041916167664 x 100 = -1.05%