"I showed you how I got the percentage."
The procedure you outlined above makes no sense. To determine the overall percentage of Canadian Homosexuals who failed to marry during the eight years of availability, One would divide the total number of unmarried Canadian Homosexuals by the Total of all Canadian Homosexuals, and multiply by 100.
The overall Canadian population, and the mysterious 2.5% factor, are irrrelevant.
In the above I am assuming that the numbers of Canadian Homosexuals who died in the past eight years, and their marital statii, are negligble. Also note that I specify married Canadian homosexuals rather than number of same-sex marriages, the latter figure is too small by half.