Actually, effective Oct. 1, 2011, you're now required to give individual income, not household. The exception is if you live in a community property state (Texas, California, etc).
The Federal Reserve's rule told credit card companies that they no longer can consider household income when assessing the creditworthiness of an individual who applies for his or her own card. Under the rule, only an individual's own salary or other income -- rather than combined household income -- can be considered.
Link
(Thanks to CVG_Kid to enlightening me recently.)