And murders are illegal by law, so they never happen. There's entire companies whose raison d'etre is to provide foreign IT labor at cheaper prices. And they aren't held accountable for it, unlike murders; those at least are generally followed up on. Here's a source: http://www.infoworld.com/article/3004501/h1b/proof-that-h-1b...
By the way, it'd be worth spending some time sanitizing your data so that it displays correctly. It sucks that the data comes in an annoying format, but it would still be way more usable if it were fixed, certainly at least the top several hundred companies. It is interesting data though -- I'm looking up some data on my previous job, and all of the foreign workers made significantly less than me. I didn't even realize that this data was available by law, so nice job on putting it online in a browsable format.