How long does Google host a video?

Once it's uploaded, provided it's not requested to be deleted, how long
does Google host a video? I'm thinking of hosting promo videos from
my company here and using the new "put on site" feature to use them on
my company's website.

However, I don't want them to disappear - so I'm looking to find out
how long Google Video will host a file.

Would prefer a link showing this, so I can have some proof. As of
now, I've been unable to locate this in Google Video's Help section.

Thanks.