Many states had (although a few still do) a second tier of accountant qualification in addition to that of CPA, usually entitled "Public Accountant" or "Licensed Public Accountant" (with designatory letters "PA" or "LPA"), although other titles have included "Registered Public Accountant" (RPA), "Accounting Practitioner" (AP), and "Registered Accounting Practitioner" (RAP). Such designations served to help regulate the practice of public accounting in that state by grandfathering through licensure non-CPA accountants who were already practicing public accounting before a regulatory state accountancy law was enacted. The majority of states have closed the designation "Public Accountant" (PA) to new entrants, with only five states continuing to offer the designation. Many PAs belong to the National Society of Accountants.