carrier	count(*)
WN	296293
AA	176203
MQ	145630
US	135987
UA	128174
OO	127426
EV	101796
XE	99915
DL	93675
NW	90429
CO	76662
YV	67905
FL	59460
OH	59034
B6	50740
9E	46948
AS	42830
F9	23035
AQ	4299
HA	2746