This link from HRSDC Canada might help regarding future NOC trends:::
http://www.rhdcc.gc.ca/eng/publications_resources/research/categories/labour_market_e/sp_615_10_06/LA06-Shortages-29Jan07.pdf
However - keep in mind that this list was published in 2007 - before the Global Economic Crisis. Since 2008 when the Global Economic Crisis came up - things have changed drastically for some professions and so there might be variations from the above list.
But still the list might be a good benchmark for things to come in the near future for Canadian Immigration.
http://www.rhdcc.gc.ca/eng/publications_resources/research/categories/labour_market_e/sp_615_10_06/LA06-Shortages-29Jan07.pdf
However - keep in mind that this list was published in 2007 - before the Global Economic Crisis. Since 2008 when the Global Economic Crisis came up - things have changed drastically for some professions and so there might be variations from the above list.
But still the list might be a good benchmark for things to come in the near future for Canadian Immigration.