4. (8 points) In another 12 days, it will be 2016, Hao Hao sighs: I have only experienced 2 leap years so far, and the year I was born is a multiple of 9. So how old will Hao Hao be in 2016?
4. (8 points) In another 12 days, it will be 2016, HaoHao sighs: I have only experienced 2 leap years so far, and the year I was born is a multiple of 9, so in 2016, HaoHao is $\qquad$ years old.

【Solution】Solution: HaoHao has only experienced 2 leap years so far. Counting backwards from 2015, the two leap years are 2012 and 2008,
Therefore, HaoHao was born between 2015 and 2004, and the year that is a multiple of 9 is 2007,
So HaoHao was born in 2007,
$2016-2007=9$ (years old)
Answer: In 2016, HaoHao is 9 years old.
Therefore, the answer is: 9.