Plotting yearly and monthly data in the same graph

Hi all,

I have two variables. Let's say I observe variable M each month. However, for variable Y, I only have one observation each year. Is there a smart way to plot these two variables in the same graph?

Obviously, I can have the Y variable for each first month (plus eleven missings for the other months of the same year), but I was wondering if anyone has thought of another way. Ideally, I want a line rather than a scatter.

Thanks!