Coefficients q_jk estimated from physical pairs as functions of G. Results for q₁₂ are considered insignificant and set to zero when fitting the other five coefficients. The different symbols represent different selections onρΔμ: 0–0.5 arcsec mas yr⁻¹ (red circles), 0.5–1 arcsec mas yr⁻¹ (green triangles), 1–2 arcsec mas yr⁻¹ (blue squares), and 0–2 arcsec mas yr⁻¹ (filled black circles with lines and error bars). The dashed blue line is the global fit in Table 7. The vertical grey lines show the breakpoints for the basis functions in G defined by Eq. (A.2).