The monthly growth rate is the annual growth rate divided by 12, because there are 12 months in a year.
monthly rate = 15% ÷ 12
monthly rate = 15/100 ÷ 12
monthly rate = 15/100 × 1/12
monthly rate = 15/1,200
monthly rate = 1.25/100
monthly rate = 1.25%
The monthly growth rate is 1.25% or approximately 1.3%
Enter 1.3 in the box