 The upgrade was also quite expensive and the ships didn't serve much longer after the modification.For example, USS "Gridley" (CG-21) received NTU in 1991 at a cost of $55 million, but was decommissioned in early 1994.The "Leahy" class (and near sisters of the ) were taken out of service in the early 1990s as part of the Clinton Administration's desire to reduce defense spending in light of reduced tensions with Russia.