simpleLoess() warning message with ggplot call

I am running the following ggplot call:

ggplot(IL2, aes(x=Year, y= Mwhs, col=Source)) +
  geom_point() +
  geom_smooth(aes(x=Year, y=Mwhs), se=F)

The plot that shows up looks ok, but it gives me the following error messages:

Warning messages:
1: In simpleLoess(y, x, w, span, degree = degree, parametric = parametric,  :
  Chernobyl! trL>n 6
2: In simpleLoess(y, x, w, span, degree = degree, parametric = parametric,  :
  Chernobyl! trL>n 6

What are these warnings referring to?