Singapore pay higher than anywhere else?

I just got paperwork for a few of my offers. I noticed that Singapore is paying the equivalent of roughly $6,000 USD per month (about $1500 a week), which is about $72,000 annually. I know most firms pro-rate a first year's ($60k) salary... why is Singapore so high? There is no singing bonus, but flight and housing are both covered.

For comparison, HK offers $1250 a week (plus flight & lodging, no signing) and NY slightly above $1200 (w/ 2k signing).