For every 1,000 petitioned delinquency cases, 4 were waived to criminal court
In 2011, U.S. courts with juvenile jurisdiction handled more than 1.2 million delinquency cases. More than half (54%) of these cases were handled formally (i.e., a petition was filed requesting an adjudication or waiver hearing).
Of the petitioned delinquency caseload, about 1% resulted in judicial waiver to adult criminal court. The number of delinquency cases judicially waived peaked in 1994 at 13,600 cases, more than double the number of cases waived in 1985.
In 2011, juvenile courts waived to an adult criminal court an estimated 5,400 delinquency cases, 61% fewer cases than in 1994.
Source: http://www.ojjdp.gov/pubs/248410.pdf .