| 2009 | 2010 | 2011 | 2012 | 2013 | 2014 |
Abnormal | 1 | 1.220 | 1.558 | 2.137 | 3.188 | 4.300 |
Airline | 1 | 1.205 | 1.368 | 1.952 | 2.800 | 3.878 |
Flow control | 1 | 1.456 | 1.801 | 2.375 | 3.828 | 4.780 |
Weather | 1 | 1.041 | 1.461 | 1.967 | 2.936 | 3.959 |
Others | 1 | 1.177 | 1.958 | 2.670 | 3.851 | 5.554 |