Absolutely. The employee contribution as a percentage of earnings (up to the maximum) was 1.8% from 1966 until 1987 when it increased to 1.9%.  From 1988 to 2003 there was a steady increase in the rate up to 4.95%.  The increase was the direct result of dire warnings that CPP would be insolvent within 20 years if the program wasn't changed.

Your employer or the self-employed of course double that contribution for the respective period.  Which is a cost ultimately borne by the employee in foregone pay increases.

Current government policy is to increase the contributions by another full 1% within the next 8 years.  

So we have gone from a program that cost employees 3.6% to one that currently costs almost 10% increasing to 12% in the near term.