What should be the income to list on a credit card application?

You should enter your current salary as an annual amount. In your example, that would be $AAA.

The credit card company does not care about your past income; they only care about your current and future income. They ask you to express it an an annual amount to avoid confusion, but it really has nothing to do with the past or the current calendar year. They just want to know what you are currently bringing in.

Ben Miller's answer is certainly accurate, but there's another angle that you should be made aware of.

Under the 2013 amendment (PDF) of the federal regulations regarding the Credit Card Act of 2009, persons 21 and older may report their total household income as their own personal annual income on a credit card application, provided that they have a reasonable expectation of access to household funds.

In other words, you may combine the annual income of yourself and your spouse / partner / significant other with whom you share a household if you typically share household expenses and expect that the other person would help pay your debts if you were unable to pay on your own. In fact, you may both use the combined total on all of your credit card apps. You don't need to disclose the fact that you are reporting total household income -- this is your right under federal regulations. Note that a credit card application may explicitly tell you not to include income of another member of your household as income -- this is allowed by regulation -- and in that case you would only list your own income . . . or pick a different credit card to do business with!

The rationale behind this amendment is that it affords equal credit treatment to both parties when one works outside the home and one is primarily a stay-at-home parent.

Excellent answers here about spousal income and salary, and using your forward-looking income. I have one addition. If you have regular bonus income, stock income, or other generally expected compensation, which may or may not include 401k matches and things like (employer, 100% nothing-out-of-pocket) covered healthcare, those may be fair to include. It never hurts to have more available credit.