benefits for family workers under compulsory coverage for pension insurance. Participation in employer's health insurance was extended to four million employees. A Development Law of December 1970 made it possible for all employees voluntarily to become members of the statutory sickness insurance. The level of income for compulsory sickness insurance was indexed to 75% of the respective assessment level for pension insurance, while voluntarily insured employees were granted a claim to an allowance towards their sickness insurance from their employer. This law also introduced a new type of sickness insurance benefit, namely facilities for the early diagnosis of disease. Apart from the discretionary service of disease prevention which had existed since 1923, insured persons now had a right in certain circumstances to medical examinations aimed at the early diagnosis of disease. According to one study, this marked a change in the concept of sickness insurance: it now aimed at securing good health. The Hospital Financing Law (1972) secured the supply of hospitals and reduced the cost of hospital care, "defined the financing of hospital investment as a public responsibility, single states to issue plans for hospital development, and the federal government to bear the cost of hospital investment covered in the plans, rates for hospital care thus based on running costs alone, hospitals to ensure that public subsidies together with insurance fund payments for patients cover total costs". The Benefit Improvement Law (1973) made entitlement to hospital care legally binding (entitlements already enjoyed in practice), abolished time limits for hospital care, introduced entitlement to household assistance under specific conditions, and also introduced entitlement to leave of absence from work and cash benefits in the event of a child's illness. In 1971, to encourage the growth of registered family holiday centres, the Federal Government granted subsidies for the building and appointing of 28 of these centres at a total cost of 8 million DM. Free preliminary investigations were introduced for 2.5 million children up until the age of 4 for the early detection and correction of developmental disorders, and health research was expanded. Federal grants were increased, especially for the Cancer Research Centre in Heidelberg, while a Federal Institute for Sport Science was set up, together with the Institute for Social Medicine and Epidemiology in Berlin. In addition, funding for new rehabilitation facilities was increased. Pensions The Pension Reform Law (1972) guaranteed all retirees a minimum pension regardless of their contributions