* Annual rate of 0.5 pct is the lowest since October 2009
* Below 0.7 pct forecast and Bank of Canada target range
* Core inflation falls to 1.0 pct from 1.1 pct
* Drop in gas prices the main trigger for overall drop
OTTAWA, Feb 22 (Reuters) - Canada's annual inflation rate in January dropped to a three-year low of 0.5 percent from 0.8 percent in December, largely due to lower gas prices, Statistics Canada said on Friday.
The rate is less than the 0.7 percent predicted by market analysts and far lower than the Bank of Canada's 2.0 percent target, offering further proof that the central bank is under no pressure to raise interest rates. The annual rate was the lowest since the 0.1 percent recorded in October 2009.
The Bank of Canada's closely watched core rate, which excludes the prices of items such as energy, tobacco and some foodstuffs, slipped to 1.0 percent from 1.1 percent in December.
The main factor behind the drop in the all-items annual rate was gas prices, which fell by 1.8 percent in the 12 months to January compared with a 1.0 percent year-on-year increase in December. Excluding gasoline, annual inflation was 0.6 percent.
Cheaper clothing also contributed to lower inflation, while the rise in food prices fell to 1.1 percent from the 1.5 percent advance seen in the 12 months to December.