A unicameral parliament ('''') holds legislative power. A second chamber, the ''House of Counties'', set up in 1993 according to the 1990 Constitution, was abolished in 2001. The number of Sabor members can vary from 100 to 160. They are all elected by popular vote to serve four-year terms. The sessions of the Sabor take place from 15 January to 15 July, and from 15 September to 15 December. The two largest political parties in Croatia are the Croatian Democratic Union and the Social Democratic Party of Croatia.