If you want to increase something by 3%, you would ADD 100% to it, so:
3% + 100% = 103%
Then you divide it by 100 to turn it into a decimal, so:
103% / 100 = 1.03
So to increase by 3%, the multiplier would be 1.03
If you wanted to decrease by 3%, you would SUBTRACT 100% from 3%, so:
100% - 3% = 97%
And then you would divide 97% by 100 to turn it into a decimal (multiplier), so:
97% / 100 = 0.97
So to decrease by 3%, the multiplier would be 0.97
