The qualifying years are more generous under the US SSD. The following table appears in a publication by the Social Security Administration:
So, what percentage of the population receives SSD or CPP-D? In Canada in 2013, there were 22,851,645 people aged 18 to 6 and an average of 234,423 CPP-D recipients... but remember Quebec, which has a similar program, had 74,893 recipients in late 2012 for a total of 309,316 disabled workers in receipt of CPP-D or the Quebec equivalent. For Canada, 1.35% of the working age population (18 to 64) is in receipt of either CPP-D or disability under the QPP —a significant percentage but substantially lower than the 4.7% noted for the US SS-D.