version 1: 1567001-2330800 1958-1969 (8 element)
version 2: 2358301-2485200 1970-1971 (6 element)
version 3: 2538251-2899400 1972-1977 (6 element)
version 4: 2974251-3880946 1979-1999 (7 elements)
version 5: 3731291-now 1997- now (7 elements)
