Original number of megalithic tombs in Germany
Many megalithic tombs have been destroyed over the centuries and the remaining buildings represent only a fraction of the original number. E. Sprockhoff [Sprock65] listed 900 for German Empire in 1938. Today this number is around 1,350 for that area. In Denmark today 2,067 tombs are known on an area roughly half the size than the megalithic areas of Germany. The estimates of the original number of buildings in the TRB area vary. In Denmark it is thought to be three times as much as today, i.e. around 6000. In Schleswig-Holstein, Germany the degree of destruction was much higher and up to 95 % of the original building might be lost. That means with around 300 buildings today the original number might have been around 6000 in this area of Germany (estimate: Landesmuseum Schl.-Holstein).
Map from 1861 showing 45 megalithic buildings and a number of round barrows
This number seems to be high on a first glance, but a very intimate documentation of the degree of destruction was given by Sprockhoff: In an area East of Neumuenster 45 Megalithic buildings were listed in a map from 1861. Today only 2 survived and it is actually unknown how many building were destroyed before the 19th century.