I would also guess the AF, but I want to add that you might see these numbers change a lot in the near future since the commercial airlines are starting to hire at a faster pace than the last 15 years. They have even upped the bonus, but the rate signing on is lower than they wanted.
I am just saying that the rates of remaining for 20, can vary alot depending on how our economy is doing. Nobody that winged in 1992, with the ability to walk in 2001 could predict 9/11. They could not predict airlines not hiring for over a decade. Thus, we truly can't say what the rate would be really like from a historical data. They only started hiring in the past 2 years. Thus, you maybe able to only find 1 year of data.
Finally, the AF has always been known to be the corporate branch, not on the flight schedule for the day and you will be able to get home in time to shuttle the rugrats to soccer practice. 8-4 is common, even at the Pentagon you will see a mass exodus between 4-4:30. Their deployments typically are 4 months, with 12 months back home. The joke is that as soon as they put in the runway, they than build the O Club, followed by the golf course. Their housing is usually ranked at the top all branches. All of this occurs impo because the AF calls rated officers the million dollar men/women since it costs that much to train them.
~ You owe 9 years upon winging, and don't be fooled they know why this is also a perfect time. At this time they are usually up for O4 and being thrown hundred thousand+ (50% up front) to hang. Won't swear, but I believe fighter pilots are now being offered 225K to stay until 19 years. Heavies have a different bonus program. Take it and sure as sheaat you are going to stay until 20.
~~ The thing is now look at from that pilot's perspective. They are about 33. Many are married, have kids, a mtg maybe and 2 car pmts, that bonus on top of O4 pay looks pretty appealing compared to the low pay airlines start pilots off on for the first 3-5 years. It becomes a financial decision, and taking 3 more tours with 50% base pay for retirement starts to look a lot better. Add in the idea that at this marker you maybe flying in Arkansas or SC and want to move back home in the state of California, where that 40K starting salary means your spouse that was a stay at home parent, now needs to get a job for several years until you move from the left seat to the right. All of the sudden that money (bonus) is very alluring.
~~~ JMPO, the ones that do leave at 33, have spent years of investing so they can walk away. Our DS is a heavy pilot. He always thought he would do 20, but right now he is doing heavy investment so if he decides to leave at 33, his wife will still be able to stay at home with their children. He squirrels away a lot of money, to the angst of my daughter in law. Don't get me wrong, they live a nice life. Purchased a beautiful home at 24, 2 cars less than 3 years old, 1 is already paid off. However, he makes sure that they can live only off of his salary. Her salary is completely invested. He reminds her that he is doing this because if he does walk at the 9 year marker, she will be able to stay at home because they can dip into savings for the 1st few years.