Figure 1. Number of SOAs in existence over time and the distribution of component holdings.
(A) Shows the monthly number of SOAs in existence from their inception in late 2001 to mid-2008. (B) Shows the distribution of the number of component holdings that comprise each SOA; the x-axis has been truncated to remove the outlier SOA containing 250 holdings for display purposes.
doi:10.1371/journal.pone.0035089.g001