The BCO is based on the PCUS Book of Church Order declared it in force on May 19, 1879. The distinction between pastors and elders in the PCA is a mixture of two traditions. The PCA holds to a quasi-parity of pastors and elders (named Ruling and Teaching Elders; REs and TEs for short), where Ruling and Teaching Elders have the same voting rights in the courts of the church and can participate in each other's examinations and ordinations, yet there are certain and definite ways that TEs and REs are distinct. Pastors have deference as moderators of local church Sessions. Only Pastors may administer the sacraments and ordinarily only pastors may preach (REs must be licensed by a presbytery if they wish to preach regularly). Also, REs are members of their local churches, while pastors are members of their presbyteries and not members of the local churches they serve. While this 2.5 office view is the consensus of the PCA, many would hold to a more Northern three-office view and others would hold to a more Southern two-office view. Church government is exercised at three levels: the Session, which governs the local church; the Presbytery, a regional governing body, and the General Assembly, the highest court of the denomination. The PCA is committed to a principle of voluntary association and all PCA congregations own their own property. Additionally all giving to the administration and permanent committees of the PCA is voluntary. The PCA does not have Synods, which some other groups have either as the highest court or as an intermediate court between presbyteries and the general assembly. The PCA is one of the fastest-growing denominations in the United States, having experienced steady growth since its founding in 1973. As of December 31, 2011, the Presbyterian Church in America had 1,771 churches (includes established churches and new church plants) representing all 50 U.S. states, the District of Columbia, Puerto Rico and 5 Canadian provinces. There were 351,406 communicant and non-communicant members. The PCA has 83 presbyteries or regional governing bodies. The latest formed in January 2014. In 2012 the PCA had 1,777 congregations – 1,474 particular and 303 mission churches – that means a net increase of 6, membership developed by 12,613 total of 364,019. The number of ordained PCA ministers are 4,321. The PCA had 384,793 members in 1,927 congregations served by 4,951 ordained ministers in 2017.