In recent years, a rapidly increasing demand for telephone numbers in a competitive environment has required numerous area code splits, overlays, and number optimization measures.  In this report, we summarize the third systematic collection of comprehensive data on the utilization of telephone numbers within the United States.  The underlying information was acquired from carriers holding numbering resources and was analyzed as part of our ongoing assessment of the numbering resource optimization measures prescribed by the Commission’s recent Numbering Resource Optimization (NRO) Orders.  The reported data show that of the roughly 1.2 billion numbers held by reporting U.S. carriers, about 40% are assigned to subscribers and are in active use, about 50% are available for use, and the remaining 10% are dedicated to administrative and other purposes.

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