L_Sio/L_bol versus ratios of 22 GHz H₂O (upper) maser and Class I CH₃OH maser luminosities (lower) and L_bol toward sources with both detections of SiO and masers. The colors indicate dust temperatures. The black dashed lines and gray shade regions are the best-fit and the 95% confidence intervals of fitting. The cyan open circles indicate sources considered to show no significant sign of SiO wings.