anatomy of time cycle:

30 yrs  = 12x30= 360 months
22.5yrs= 3/4 = 270 months
20 yrs=2/3=240 months
15 yrs =1/2=180 months
10 yrs =1/3=120 months
7.5yrs =1/4=90 months
5 yrs =1/6th =60 months
3yrs= 1/8th=45 months