It’s difficult to put a finger on the exact cause of the recent surge in popularity of commodity investing. More than likely, the boom is attributable to a number of different factors. Correlation between international equity markets (and even between stocks and bonds) has surged in recent years, increasing both the importance and difficulty of adding non-correlated assets to investor portfolios.

Given the relatively weak correlation with other asset classes, commodities have found a home in many investors’ portfolios. Moreover, unprecedented injections of liquidity into the financial system have created anxiety over a coming uptick in inflation that could erode returns to stocks and fixed income instruments. Commodities have historically served as an effective inflation hedge, and many are once again turning to natural resources to protect assets from a surge in the CPI.

What a difference a year makes. At this time in 2009, it seemed that the markets and exchange traded funds couldn’t sink much further. Little did we know, a reprieve was to come. Here are eight of the strongest ETFs since that day.

Market Vectors Coal ETF (NYSEArca: KOL) is up 224.9% off the low. Oil prices topping off in the low $80 range helped boost coal plays since March 9. Coal prices had an assist in recent months as those in the colder climes crank up the heat and push demand higher, eating into what had been a surplus. And last year, China shifted from being a coal exporter to an importer, shifting the dynamics of pricing.

March 9, 2009 is a date etched into the memories of many investors. After months of unprecedented volatility, depressing statistical releases, and countless false bottoms, that’s the day most equity markets finally hit their lows. It also marked the beginning of an impressive rally that saw most major indexes climb steadily for the remainder of the year, reclaiming big chunks of the ground lost during the downturn. While the “great rally of ‘09″ boosted most asset classes (and their related ETFs), some performed far better than others.

Below, we highlight the ten non-leveraged ETFs that have delivered the best performances in the twelve months following the bear market lows hit in March 2009: