Which is correct:
"about half an year ago" or "about half year ago"?

Some examples from the web:

• I remember talking about this for the first time in Australia, about one and a half years ago, when their academy honored me with a fellowship.
• The ministerial conference of Helsinki which took place about three-and-a-half years ago took our requirements into consideration.
• He worked maintenance on the railroad and got fired about nine and a half years ago.
• Until about 15 years ago half of Europe did not enjoy freedom and democracy.
• He went out one night about three and a half years ago to get a couple beers and a Powerball ticket.
• About three and a half years ago I made a discovery.
• Well, we subpoenaed your records, and they show that you treated Mr. Wicker about nine and a half years ago.
• Madam President, about five and a half years ago, I caused something of a furore by suggesting that any small businessman with his brain in the right place would be mad to employ a woman of childbearing age.
• But when Nicholas Negroponte - and he has spoken about this project a lot, he's the founder of OLPC - came to us about two and a half years ago, there were some clear ideas.
• About four-and-a-half years ago... I met a real-estate agent named Lisa Kramer... who showed me an apartment, which I rented... just so she'd go out with me.
• I would remind you that it was about two and a half years ago that the Commission kicked off a new initiative, having come to the conclusion, following the Kok report, that the Lisbon Strategy needed to be got back on its feet again.
• Somebody was up at my house and saw the paintings and recommended them to a gallery, and I had a first show about two-and-a-half years ago, and I showed these paintings that I'm showing you now.
• About three and a half years ago I made a discovery. And this discovery profoundly changed my view on how I thought the world worked,
• He went out with my sister for about half an hour.
• - He checked in about half an hour ago.
• This should knock him out for about half an hour.
• I saw Goran leave about half an hour ago.
• The panels in the ceiling only depress about half an inch.
• It was about half an hour from a place called Medjugorje.
• He left about half an hour ago.

Some examples from the web:

• I remember talking about this for the first time in Australia, about one and a half years ago, when their academy honored me with a fellowship.
• The ministerial conference of Helsinki which took place about three-and-a-half years ago took our requirements into consideration.
• He worked maintenance on the railroad and got fired about nine and a half years ago.
• He went out one night about three and a half years ago to get a couple beers and a Powerball ticket.
• About three and a half years ago I made a discovery.
• Well, we subpoenaed your records, and they show that you treated Mr. Wicker about nine and a half years ago.
• Madam President, about five and a half years ago, I caused something of a furore by suggesting that any small businessman with his brain in the right place would be mad to employ a woman of childbearing age.
• Until about 15 years ago half of Europe did not enjoy freedom and democracy.
• But when Nicholas Negroponte - and he has spoken about this project a lot, he's the founder of OLPC - came to us about two and a half years ago, there were some clear ideas.
• About four-and-a-half years ago... I met a real-estate agent named Lisa Kramer... who showed me an apartment, which I rented... just so she'd go out with me.
• I would remind you that it was about two and a half years ago that the Commission kicked off a new initiative, having come to the conclusion, following the Kok report, that the Lisbon Strategy needed to be got back on its feet again.
• Somebody was up at my house and saw the paintings and recommended them to a gallery, and I had a first show about two-and-a-half years ago, and I showed these paintings that I'm showing you now.
• About three and a half years ago I made a discovery. And this discovery profoundly changed my view on how I thought the world worked,
• The President was making speeches about this around three and a half years ago.
• Mr President, as soon as I became a Member of this Parliament two and a half years ago, I asked Commissioner Reding what she intended to do about the precarious situation European cinema found itself in.
• This is Amelia's birthday party three and half years ago.
• Ashley Robert Boyall, ex-army, registered address Easton, released two-and-a-half years ago.
• Laura bought it a half year ago.
• Mark Wyman was killed four and a half years ago.
• Two-and-a-half years ago, I fainted from exhaustion.