Cross correlation results for the 18 diseases with the highest Spearman’s rho values (2009–13). Cross correlations for two search terms are displayed for each disease. Coloured bars correspond to the search term with the highest Spearman’s rho value for each disease (red bars indicate values that exceed the 95% confidence interval, whereas blue bars do not). Unfilled bars indicate cross correlation results for alternative search terms with highest cross correlation values at a lag value of 1. Confidence intervals (95%) are indicated by the grey lines.