Data that fits a sinusoidal regression curve tends to fluctuate over time in undulating or wave-like curves. For example, temperatures from year to year tend to undulate in a sinusoidal pattern. Sinusoidal waves are also commonly seen in signal processing and time series analysis.
use this formula
y~asin(bx+c)+d
a:11045.5
b:0.0328144
c:1.46343
d:44570.7