CEC category is just one small group of immigrants.
Background/security check for any Canadian embassy in the world, and for all immigration applications will be processed by Government of Canada.
Unfortunately, officers in embassies or processing offices are not responsible for that, and they have to wait for an answer from responsible organization.
e.g. If PanAM games require 20,000 visas in a short time, then government have to prioritize background check over something else. (not saying this is the reason of our delay, as we don't know)
You can read the number of applications, and even average of processing time for background check, security check, etc. in yearly reports of CIC website.
One example of report for 2013:
http://www.cic.gc.ca/english/resources/statistics/facts2013/permanent/01.asp