This is an interesting article from a few years back:
Western People - 2003/12/24: Knock airport is flying high as passenger numbers soar
It is easy to forget that as recently as seven years ago the airport was still seen as a white elephant in the bog and had only three scheduled international routes (Stansted, Birmingham and Manchester) in comparison to the 15 that are lined up for next year to date. (I say to date because I am still hopeful of something to Edinburgh - its been rumoured for some time now)