From 21 December 1949 to 3 May 1953, foreign-exchange conversion rates of the Bank deutscher Länder (the predecessor of the Deutsche Bundesbank). From 4 May 1953 to 30 December 1998, official quotation on the Frankfurt exchange (difference between buying or selling rate and middle rate DEM 0.110). From 1 January 1999, irrevocable euro conversion rate: EUR 1 = NLG 2.20371.