Federal criminals have gotten slightly longer prison sentences since the Supreme Court struck down mandatory sentencing guidelines a year ago, but a congressional leader complained Wednesday that sex offenders appear to be getting a break.

House Judiciary Committee Chairman James Sensenbrenner, R-Wis., said that his committee would begin drafting a new system for sentencing people convicted in federal courts.

The Supreme Court's ruling 14 months ago rattled the criminal justice system when it invalidated the nearly 20-year-old mandatory sentencing system, thereby giving judges more freedom to decide for themselves what a fair sentence is.

Bush administration lawyers and some lawmakers complained at the time that rogue judges could be soft on criminals.

There was no widespread evidence of that in a detailed 277-page report released by the U.S. Sentencing Commission, a panel that sets guidelines which are now optional, not mandatory like in the past.

About 67,000 people were sentenced over the past year to an average 58 months in prison, compared with 57 months from the previous year.

"Things haven't changed all that much," said Douglas Berman, a sentencing expert and law professor at Ohio State University.

In nearly nine out of 10 cases, the judges sentenced criminals within the guideline ranges, accepted the prosecutor's recommendation to be more lenient or gave a tougher penalty, Berman said. "There's no need for a dramatic change," he said.

Although sentences for sex crimes remained steady, Sensenbrenner said there was a 50 percent increase in sentences below the recommended guidelines for defendants convicted of sexual contact of a minor, trafficking in child pornography and possession of child pornography.

"Unrestrained judicial discretion has ... jeopardized the basic precept of our federal court system that all defendants should be treated equally under the law," he said.

Among other findings in the report:

--Men received longer prison sentences than women.

--Black and Native American defendants received longer sentences than whites and Hispanics.

--Non-citizens were given longer sentences than Americans.

Some judges fear that Congress could rush to adopt a new plan that also would be flawed, and prompt more appeals.

Under the previous system, judges made factual decisions that affected a person's prison time, such as the amount of drugs involved. The high court ruled 5-4 that juries, not judges, should make those determinations.

"We may be back where we started from," U.S. District Judge Thomas F. Hogan told reporters this week.