FWIW my Permanent Residency came in way faster than the time that was published at the time.

The estimate is based on "processing time from receipt of application to final decision for 80% of cases".

The rather excellent British Expats (not just for Brits!) forum users keep track of the various processing times of Canadian immigration applications.

http://britishexpats.com/forum/forumdisplay.php?f=33

British Expats forums is a great resource for anyone trying to move within the English speaking world.