Table 13. System* Passenger Revenue Yield (Cents per Mile),,,,,,, Passenger Airlines by Group ,,,,,,, Ranked by 1st Quarter 2007 Revenue Yield ,,,,,,, (Passenger Revenue per Revenue Passenger Mile in cents),,,,,,, 1Q 2007 Rank,Carrier Group,1st Quarter 2006 ,2nd Quarter 2006 ,3rd Quarter 2006 ,4th Quarter 2006 ,1st Quarter 2007 ,1st Quarter Passenger Revenue $(Millions) 1,Regional ,20.5,18.9,19.3,19.7,20.3,"2,358" 2,Network ,12.1,12.7,12.6,12.3,12.5,"16,494" 3,Low-Cost ,11.6,12.3,11.9,12.1,11.9,"4,300" ,21-Carrier Total,12.5,13.0,12.9,12.7,12.9,"23,152" Source: Bureau of Transportation Statistics; Form 41; Schedule P1.2. T100; T2 Data,,,,,,, * System = domestic + international ,,,,,,,