Apply ITIN for my wife. How long will it take ?

I have an SSN. I want to apply for an ITIN for my wife.We have been in US only since Nov 2013. I want to apply - "Married. applying jointly'.
I read the forums that, i need to apply for ITIN by filling up the W7 form along with the attested copies of passport (proof that she's a foreign national), which is ok. I wanted to know, how long will it take to get the ITIN for my wife ? Weeks or Days ?