A government study released yesterday has found that sex offenders are less likely to be rearrested after their release from prison than other criminals.  The Justice Department study of 9,691 men convicted of rape, sexual assault and child molestation who were released in 1994 found that 43 percent were arrested for any type of crime within three years, compared with 68 percent for all other former inmates.  The study found 53 percent of sex offenders were arrested for another sex crime after their release.  The study examined prison releases in 1994 from Arizona, Maryland, North Carolina, California, Michigan, Ohio, Delaware, Minnesota, Oregon, Florida, New Jersey, Texas, Illinois, New York and Virginia.  Sex offender recidivism rates for the individual states were not included by the researchers.