Inside traders have more to fear when they stand before Manhattan federal judges for sentencing.

Since Jan. 1, 2011, the judges have sent the average violator to prison for more than 22 months, according to an analysis of sentencing data by Bloomberg News. That was a 20 percent increase from the average term of 18.4 months during the previous eight years.

The harsher sentences come three years into a federal crackdown on insider trading on Wall Street.

Since August 2009, federal prosecutors in Manhattan have charged 71 people with insider trading and won 65 convictions, with six cases still pending. Some of those convicted, including former Goldman Sachs Group Inc. (GS) director Rajat Gupta, are awaiting sentencing.

Source: Bloomberg