The Czech Republic has a well-developed social security system, and employers, employees and self-employed persons contribute to social security schemes. The Czech social security system is built on three pillars: compulsory social insurance, state social support system and social assistance. Compulsory social insurance covers pension insurance, health insurance and the national employment policy system. The non-contributory state social support system supports families with dependent children. The final pillar, tax-financed social assistance provides benefits to persons with disabilities, and assistance to those with insufficient income. The sickness insurance scheme is obligatory for employees, and voluntary for self-employed persons. Some groups such as students and women on maternity leave are insured without contributions, if certain conditions are met.