Serial number range: 332001-2077500 (1936-1964, approx. 7,150 produced). Production by year: 1936: #332001-332050 (50 units); 1939: #492001-492100 (100 units); 1940: #540501-540550 (50 units); 1941: #567001-567050 (50 units); 1950: #824001-824100 (100 units); 1952: #982001-984100 (2,100 units); 1953: #1097001-1098000 (1,000 units); 1956: #1366001-1366500 (500 units); 1957: #1486001-1486700 (700 units); 1958: #1616001-1645300 (500 units); 1960: #1746501-1747000 (500 units); 1961: #1875501-1876500 (1,000 units); 1964: #2077001-2077500 (500 units).