Effective rotation rate versus solar cycle, calculated with Eq. (14). Solid black line represents the ADAPT-GONG magnetograms using R_ss = 2.5 R_⊙, and the observed surface rotation rate. Dashed lines indicate the equatorial, polar and Carrington rotation rate. The solid grey line instead uses the less-extreme coronal hole rotation profile (see Appendix A). PFSS models shown in Fig. 3 are highlighted with black circles. The daily, monthly, and monthly smoothed sunspot number from the Sunspot Index and Long-term Solar Observations (SILSO) are displayed in the background of the figure with a solid green lines of varying opacity.