It all depends on the complexity of each applicant's case, officer's work tempo and the immigration program you chose. In addition, possibly the country you are from is the factor that could affect the processing rate. Rumour has it that if your country has the visa-free treaty with Canada, the application processing time could be shortened due to the quick-accessed information-sharing resource and the highly cooperative spirit between each other.
I agree with what Josh_math says.I come from a visa exempted country and in February will be 19 months, so not too much gained. DM on Jan 6, application received on July 26.
I also came from visa exempted country and waiting 17 damn long months.