The Croatian language is the official language, but minority languages are officially used in some local government units. Croatian is declared as the native language by 95.60% of the population. A 2009 survey revealed that 78% of Croatians claim knowledge of at least one foreign language—most often English. The main religions of Croatia are Roman Catholic (86.28%), Eastern Orthodoxy (4.44%) and Islam (1.47%). Literacy in Croatia stands at 98.1%. The proportion of the population aged 15 and over attaining academic degrees grew rapidly since 2001, doubling and reaching 16.7% by 2008. An estimated 4.5% of the GDP is spent for education. Primary and secondary education are available in Croatian and in languages of recognised minorities. Croatia has a universal health care system and in 2010, the nation spent 6.9% of its GDP on healthcare. Net monthly income in September 2011 averaged 5,397 kuna ( 729 euro). The most significant sources of employment in 2008 were manufacturing industry, wholesale and retail trade and construction. In January 2020, the unemployment rate was 8.4%. Croatia's median equivalent household income tops average Purchasing Power Standard of the ten countries which joined the EU in 2004, while trailing the EU average. 2011 census recorded a total of 1.5 million private households, which predominantly owned their own housing. Average urbanisation rate in Croatia stands at 56%, with augmentation of urban population and reduction of rural population.