Alcoholics Anonymous is an international mutual aid fellowship of alcoholics dedicated to abstinence-based recovery from alcoholism through its spiritually-inclined Twelve Step program. Following its Twelve Traditions, AA is non-professional and spiritual but non-denominational, as well as apolitical and unaffiliated. In 2020 AA estimated its worldwide membership to be over two million with 75% of those in the U.S. and Canada. Without endorsing the disease model of alcoholism, AA is still associated with it due to the large role many members took in making it popular. Regarding its effectiveness, a 2020 scientific review saw clinical interventions encouraging increased AA participation resulting in higher abstinence rates over other clinical interventions while probably reducing health costs. AA dates its start to 1935 with Bill Wilson first commiserating alcoholic to alcoholic with Bob Smith who, along with Wilson, was active in AA's precursor the Christian revivalist Oxford Group.