Influence of the magnetic activity cycle on frequency separation ratios, r₀₁ and r₀₂, observed by BiSON. The grey data represent the averaged shift due to magnetic activity. The full frequency range was considered (n = 14 − 24). The red line was obtained by smoothing the grey data with a Savitzky-Golay filter. The 10.7 cm radio emission flux, a proxy of the solar cycle, is denoted in black. The correlation with the activity proxy is measured with the Spearman rank coefficient, ℛ.