Average charge-state () versus solar wind proton speed for Fe-cool and Fe-hot coronal-hole type wind for 2004. The color gradient indicates the frequency of observing each charge-state-solar wind speed pair in 2004 and is normalized to the maximum in each panel. Each data point represents a four-hour average. The inset in each panel gives the number of data points in 12-min resolution that contributed to the averages in in this figure. The number (N_all) of all 12-min resolution data points in 2004 is given on the top right and the number (N_CH) of all data points categorized as pure coronal-hole wind, in the top left.