I don't know the absolute figures in terms of cases per year, but the four common coronaviruses are... common. From [1], we see that 1 in 200 flu-like infections was the coronavirus HKU1. This [2] paper corroborates and gives figures for the other three common viruses.

We can therefore assume that about 1 in 25 bad-cold or flu-like illnesses are caused by a coronavirus.

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5466428/