The three Scandinavian countries are constitutional monarchies while Finland and Iceland have been republics since the 20th century. Currently, the Nordic countries are described as being highly democratic and all have a unicameral form of governance and use proportional representation in their electoral systems. Although there are significant differences among the Nordic countries, they all have some common traits. These include support for a universalist welfare state aimed specifically at enhancing individual autonomy and promoting social mobility; a corporatist system involving a tripartite arrangement where representatives of labour and employers negotiate wages and labour market policy mediated by the government; and a commitment to private ownership within a market-based mixed economy, with Norway being a partial exception due to a large number of state-owned enterprises and state ownership in publicly listed firms. As of 2020, all of the Nordic countries rank highly on the inequality-adjusted HDI and the Global Peace Index as well as being ranked in the top 10 on the World Happiness Report.