Add ":" on the lower row of the Num row >> Num pad layer

I like the "Num row >> Num pad" layer. It’s really handy for quickly inserting numbers, years for instance. But it’s a bit painful for time, that I use to write in the HH:mm format. And I enter times very more often than dates. I think adding ":" under the 6, where the N is on the normal layer, would be a good idea.