Ans: The Institutional Revolutionary Party (Spanish: Partido Revolucionario Institucional; abbr. PRI) is a political party in Mexico that was founded in 1929 and held uninterrupted power in the country for 71 years, from 1929 to 2000, first as the National Revolutionary Party (Spanish: Partido Nacional Revolucionario, PNR), then as the Party of the Mexican Revolution (Spanish: Partido de la Revolución Mexicana, PRM) and finally as the PRI beginning in 1946.