According to the Department of Labor:
Median annual earnings of registered nurses were $48,090 in 2002. The middle 50 percent earned between $40,140 and $57,490. The lowest 10 percent earned less than $33,970, and the highest 10 percent earned more than $69,670. Median annual earnings in the industries employing the largest numbers of registered nurses in 2002 were as follows:
Employment services $55,980
General medical and surgical hospitals 49,190
Home health care services 45,890
Offices of physicians 44,870
Nursing care facilities 43,850
http://stats.bls.gov/oco/ocos083.htm