A sharp sell off in the price of crude has already taken most of the risk off the table.

We’re now well into the fourth full-fledged bear market in crude oil since the start of 2009. The first three lasted just weeks to months but saw oil prices plunge by an average of 28.3% from peak to trough.

Those declines paled next to the percentage gains in the four uptrends they puntuated. Coming out of the Great Recession oil rallied by 155% before tailing off. Ignore that huge gain as an outlier and the next three upturns still rose by an average of 51.7% before petering out.

The current sell-off has already run an abnormally long 398 days. From the last top, oil prices are now down by almost 23% (Oct. 8, 2014). The bearish action was interrupted by a tradable rally after crude had declined by about 13%.

West Texas Intermediate has fluctuated between around $70 - $105 during most of the last three and a half years. Crude has not been lower than it closed on Wednesday in more than a year, though.

Extremely negative sentiment, sharp recent declines and the excessive duration of the price trend make this look like a good spot for traders to get long. Consider buying the United States Oil Fund L.P. (USO) or the complexly-named, but cutely symbol-ed iPath S&P GSI Crude Oil Total Return Index Medium-Term Notes, Series A (OIL) ETN.

History suggests you’ll get a chance to trade out for at least a 20% - 50% gain on crude’s next rally.