Distribution of the hyperfine intensity anomalies of the inner (HIA_IS) and outer (HIA_OS) satellite lines. Arrows indicate potential corrections for the blending of the primary and inner satellite lines. The source name is marked in close proximity to each data point. Gray dashed vertical and horizontal lines divide the panel into four subregions: I for HIA_IS > 1 and HIA_OS > 1, II for HIA_IS < 1 and HIA_OS > 1, III for HIA_IS < 1 and HIA_OS < 1, and IV for HIA_IS > 1 and HIA_OS < 1. The models that cause HIAs to be located in these subregions are also labeled.