Usually it takes a few months - 2/3 months. Depends on their approach. I mean, CCR released 3 albums in 1969 (Bayou Country, Green River & Willy and The Poor Boys)... so right there is proof that you can do it quicker than a year. Many other bands have taken much longer than a year, although that doesn't mean they've been recording in a studio for more than a year.
Some artists, like Bruce Springsteen and Neil Young spent almost a year working on an album, completed it, and then discarded it completely only to restart again from scratch. I would say this counts towards the time that it takes to finally record the album that the artist feels is ready for release.
Then you get other guys like Ryan Adams who release albums at an alarming speed but with very little relevant or even good content.
So really, album time is a vague term. These days, veteran bands will take their sweet time to put an album out (Radiohead, Metallica, Green Day, Weezer, Aerosmith, U2). These guys have made their money and usually will only want to put out an album if they have something relevant to release. Newer bands try to get them out quicker to get their name out - like basically all the bands, save Weezer, that I previously mentioned, when they were younger.