How Old is my Feurich Piano?

In July 1991 the Bechstein Group bought a majority shareholding in the Euterpe Piano Company. Feurich remained autonomous  and, finding a factory just 3 miles (5km) away, spent much of the 1990s gradually increasing production. Today, with a steady output of upright and  grand pianos from the Gunzenhausen factory, Feurich is planning the production of a concert grand modeled on their beautiful instruments of the 1920s and 1930s.
Dates and serial numbers when the pianos were manufactured 

1860 400
1870 1200
1880 3900
1890 8400
1900 13900
1910 23800
1920 35100
1930 46500
1940 49600
1950 51300
1960 55150
1970 62401
1980 70000
1990 74000
2000 76200