It would only be supposition on my part but there are a number of things. Mandatory minimum penalties have had the effect of moving people from provincial custody to federal institutions. Some of the sentences at the federal level may be longer. As indicated there has been an increase in the length of sentences as well. Whether that is attributable to mandatory minimum penalties or whether that is also attributable to judicial discretion, or a combination of both, it's really hard to say the reason for the increase.
On February 23rd, 2016. See this statement in context.