To give you an idea, the comparative data for the various countries were gathered twice, to my knowledge, namely in 1999 by the Department of the Solicitor General, or the Department of Public Safety, and again in 2005 by the same department. I do not know how the countries were chosen. Usually, a request is made to various countries, and we await their responses.
If we compare Canada to other countries, we see that the system is much more punitive here. You are perfectly correct in underscoring that.