20 | | 4000~6500 | 77% | 1. 20 | | | 5 1972 | 200 350 | 5 | 1976 | FD1. | 5~100 | | 2. | 1978 | | 97 | 1980 | | | | | 139 233 | 3. | 1983 | | 1984 9 | 14 | 1989 58 | 95% | | | | | | | | 1 12~20 | 1989 | 5 100 | | |