The SD continues today, whereas the ZSL eventually evolved into today's Polish People's Party. Two of the Catholic associations with Sejm representation continue today as lay Catholic organisations. During Communist rule in Bulgaria, the Bulgarian Agrarian People's Union was the only other legal party. A number of successor parties exist in post-Communist Bulgaria. In China, North Korea and Vietnam (until 1988), bloc parties also exist, playing a subordinate role to ruling Communist parties as constituent members of official coalitions. A few examples of a bloc party system also exist in non-Communist regimes. Since the 1920s, the main centre-right force in Australian politics at the federal level has been an alliance of parties known as the Coalition: originally consisting of the Nationalist Party and the Australian Country Party, it currently includes those parties' successors, the Liberal Party of Australia and the National Party of Australia. The Coalition's formation was prompted by the rise of the centre-left Australian Labor Party, which remains the Coalition's main political opponent. The two parties of the Coalition draw support from different bases, with the Liberals gaining their votes in urban areas and the Nationals winning theirs in rural areas. Arrangements at state and territorial level vary, from the merger of state Liberal and National parties through to electoral alliances on the federal model and, in the case of Western Australia, a looser relationship. The Bulgarian Socialist Party (BSP) and other leftist parties in Bulgaria have been members of the leftist electoral alliance Coalition for Bulgaria since 1991. The Christian Democratic Union of Germany does not contest elections in Bavaria, where its place is taken by the somewhat more conservative and Catholic-influenced Christian Social Union. They form a common CDU/CSU bloc in the Bundestag. The Hong Kong pro-democracy camp has been establishing an electoral coalition in local level elections. Unless there is a coordination failure, the parties within the camp will not contest against each other in local level elections. In the coming General Election, they also launch primaries to ensure the greatest coordination and thus greatest possible number of seats, at best simple majority (35+) can be achieved. Christian Democratic People's Party is the coalition partner of the ruling party Fidesz, and runs with Fidesz on a joint electoral list. In Mexico during the rule of the Institutional Revolutionary Party (PRI, 1929–2000), partidos paleros (satellite parties) included the Authentic Party of the Mexican Revolution and the Socialist Popular Party. These helped the PRI government give the superficial appearance of a competitive democratic system.