to DM 15,000 by the third modification law (December 1971), DM 16,800 by the fourth modification law (November 1973), and to DM 18,360 by the fifth modification law (December 1973). A flexible retirement age after 62 years was introduced (1972) for invalids and disabled persons, and social assistance was extended to those who previously had to be helped by their relatives. From 1971, special subventions were provided to enable young farmers to quit farming "and facilitate their entry into the non-agricultural pension system by means of back payments". The Third Modification Law (1974) extended individual entitlements to social assistance by means of higher-income limits compatible with receipt of benefits and lowered age limits for certain special benefits. Rehabilitation measures were also extended, child supplements were expressed as percentages of standard amounts and were thus indexed to their changes, and grandparents of recipients were exempted from potential liability to reimburse expenditure of social assistance carrier. The Third Social Welfare Amendment Act (1974) brought considerable improvements for the disabled, those in need of care, and older persons, and a new fund of 100 million marks for disabled children was established. Allowances for retraining and advanced training and for refugees from East Germany were also increased, together with federal grants for sport. In addition, increases were made in the pensions of 2.5 million war victims. Following a sudden increase in the price of oil, a law was passed in December 1973 granting recipients of social assistance and housing allowances a single heating-oil allowance (a procedure repeated in the winter of 1979 during the Schmidt Administration). Improvements and automatic adjustments of maintenance allowances for participants in vocational training measures were also carried out, and increased allowances were provided for training and retraining, together with special allowances for refugees from East Germany. There was determined, by statutory regulation issued in February 1970, the category of persons most seriously disabled "to whom, with regard to maintenance aid, an increased demand (50% of the appropriate rate) is being conceded, and, within the scope of relief in special living conditions: a higher rate of nursing aid". In 1971, the retirement age for miners was lowered to 50. An April 1972 law providing for "promotion of social aid services" aimed to remedy, through various beneficial measures (particularly in the field of national insurance and working conditions), the staff-shortage suffered by social establishments in their medico-social, educational and other work.