Really need help with #20! I'll give brainliest!

Answer: 1 year (year 15)
Step-by-step explanation:
109.5-86.0=23.5
128.4-109.5=18.90
140.8-128.4=12.4
158.7-140.8=17.9
182.1-158.7=23.4
23.5+18.9+12.4+17.9+23.4=96.10
96.10÷5=19.22
200-182.1=17.9
182.1+19.22=201.32 subs