Same plot as Fig. 6, but data are averaged in [Fe/H] bins. Thin disc (thick grey solid line), thick disc (red solid line), metal-rich high-α sequence (blue dotted line), metal-poor low-α sequence (dash-dot green line), and metal-poor high-α sequence (dashed magenta line); the light grey lines represent the solar values. The binning structure is the same as in Fig. 7. The error bars represent the standard deviation associated with the mean value.