Figure 2. Box-plot of mean pairwise similarities demonstrating the genetic relatedness of serogroup C strains for persons <14 years (32 strains), persons 15–24 years (28 strains), and adults ∃>25 years (14 strains) during 1992–1999. The lower, central, and upper horizontal lines in the box indicate the 25th, 50th, and 75th percentiles. The outliers, as defined as the 25th or 75th quartile ±1.5x the interquartile range, are plotted as circles. Notches of box plots that do not overlap indicate a statistically significant difference at the <0.05 level.