(a) The number of Pfam families (dark blue) and the number of MCL clusters (light blue) that gained their first structural representative each year from 1976 to 2012. pfam_scan was used to map Pfam families to PDB chains. (b) As in (a), but using PDBfam to map Pfam families to PDB chains. (c) The number of newly covered families/clusters (i.e. the sum of the two) per 100 structures released in the PDB each year from 1993 to 2012. Newly covered families/clusters were calculated using pfam_scan (blue) and PDBfam (red).