growth of protein-DNA complexes in the Protein Data Bank

Hi,
while checking the update logs of our good old 3D-footprint, a database of DNA-binding protein structures updated weekly from the Protein Data Bank, I found a folder with logs starting Februrary, 2009. The plot below shows how the number of non-redundant complexes, filtered in terms of protein sequence identity, has doubled in just a decade:

The nr95 bundle can be downloaded in PDB format at
http://maya.ccg.unam.mx/tfmodeller/get_library.cgi

Other related files are available at:
http://floresta.eead.csic.es/3dfootprint/download.html

cheers,
Bruno