Apple Music Family Plan pricing

Has the price of a family plan for Apple Music increased? When my family and I first signed up in September of 2018 it was $10.95 CAD, and in October 2018 it increased to $14.99 CAD. Then in January of 2019 it changed again to $15.74 CAD. In July of 2019 (now) it changed once again to $16.74 CAD.

Is this supposed to be happening, or is something going wrong with our account?

If it is correct, is there any place we can go to find information on future changes?

Thanks in advance for any who answer.