Figure 2.

Growth in the complexity of PDB archival holdings 2000–2018. (a) Cumulative number of unique ligands maintained in the Chemical Component Dictionary each year. In 2018, 2,498 new entries were added. (b) Average molecular weight (solid purple line) and average number of polymer chains (solid orange line) of structures released each year. (c) Growth in available EM structure data, shown by annual accumulation of number of chains and molecular weight