The Bolivian National Telecommunications Company was privatized in 1995 but re-nationalized in 2007; the primary trunk system is being expanded and employs digital microwave radio relay; some areas are served by fiber-optic cable; system operations, reliability, and coverage have steadily improved. Most telephones are concentrated in La Paz, Santa Cruz, and other capital cities; mobile-cellular telephone use expanding rapidly and, in 2011, teledensity reached about 80 per 100 persons.[1]