these are gross popular vote totals for the conservatives since 2006 - not adjusted, not percentages, actual numbers.

there are reasons why you should start in 2006 and not earlier.

2006: 5,374,071     [36.27%] (lib martin)
2008: 5,209,069     [37.65% (+1.5%), but down 160,000 actual voters. turnout: -6%.] (lib dion)
2011: 5,832,401     [39.62% (+2%). note that turnout was +2%.]   (lib ignatieff)
2015: 5,613,614     [31.89% (-7.77%). note that turnout was +7.2%] (lib trudeau)

it's a very small window of change: 5.2-5.9 million voters. these voters are much older than the population is, too, which means they're much more likely to vote.

these are gross popular vote totals for the liberals in the same period:

2006: 4,479,415 (martin)
2008: 3,633,185  (dion)
2011: 2,783,175  (ignatieff)
2015: 6,943,276  (trudeau)

so, you can see there's a much wider range: 2.7-7.0 million voters that you can't even begin to fit into the swing on the right.