\begin{figure}[t]
    \centering
<<fig=TRUE,height=3>>=
    coverage_ordered <- reports
    coverage_ordered <- coverage_ordered[is.finite(coverage_ordered$coverage.related),]
    coverage_ordered$display_order <- unlist(by(coverage_ordered, coverage_ordered$project, function(x) order(order(x$coverage.related))))
    coverage_ordered <- melt(coverage_ordered, id.vars=c('project', 'bug_number', 'bug_id', 'display_order'), measure.vars=c('coverage.related', 'coverage.unrelated'))
    coverage_ordered$project <- format_name(coverage_ordered$project)
    coverage_ordered$variable <- format_name(coverage_ordered$variable)
    coverage_ordered$dummy <- format_name('coverage.overall')
    fig <- ggplot(coverage_ordered, aes(display_order, value, linetype=variable)) +
        geom_line() +
        facet_grid(dummy ~ project, scales='free') +
        labs(x='Bugs ordered by ascending related coverage', y='Coverage') +
        theme(axis.text=element_text(colour='black'),
              axis.text.x=element_text(angle=90),
              axis.title.y=element_blank(),
              legend.position='bottom',
              legend.title=element_blank(),
              panel.border=element_rect(colour='black', fill=NA)
        )
    print(fig)
@

    \caption{Coverage for methods related and unrelated to a bug}
    \label{fig:coverage_ordered}
\end{figure}
