Serial number range: 2406001-3617889 (1970-1993, approx. 12,663 produced). Production by year: 1970: #2406001-2407000 (1,000 units); 1971: #2494051-2495050 (1,000 units); 1972: #2524801-2546950 (2,000 units); 1973: #2660451-2661450 (1,000 units); 1974: #2694001-2695500 (1,500 units); 1976: #2782651-2783150 (500 units); 1977: #2850051-2868800 (1,500 units); 1979: #2976751-2977250 (500 units); 1980: #3050601-3076300 (1,000 units); 1981: #3108501-3109000 (500 units); 1982: #3185701-3187700 (2,000 units); 1991: #3583669-3583830 (162 units); 1993: #3617889-3617889 (1 units).