Since 2005, the Privacy Rights Clearninghouse has been tracking data breaches. They announced that in the first half of 2011 22.4 million records were breached in 275 cases. This is only the breaches that were publicly disclosed. The true number must be much higher. The important thing to remember is that some breaches are very serious when it is the work of hackers looking to steal information and some can be just an old drive that did not turn up in the inventory and is most likely already destroyed. If you do get a notification take the time to learn the threat level.