I wouldn't be able to give you an accurate figure because there are so many rotations of police officers in and out. I do know for a fact that when I was serving in mission myself, the RCMP tried to keep their numbers up to a good level. At any given time it was usually around 10%. That goes back several years ago. They are making efforts and trying to recruit more women.
The problem is that women police officers are also needed here in Canada. It's sometimes difficult to get them released by their commanding officers. The same problem exists in other countries as well. They're a very valued asset within your police force, and therefore you might be a little reluctant to release them.