Canada Pension Plan Regulations

6.1 For the purposes of subsections 10(1) and 13(3) of the Act, the salary and wages on which a base contribution has been made for the year by an individual under a provincial pension plan is an amount equal to the aggregate of all base contributions required to be made by the individual in that year under a provincial pension plan in respect of salary and wages, divided by the base contribution rate for employees under the provincial plan for the year.