A Test for the Existence of God

[TheQ]

I've been reading the bible lately (for the first time) and it always seems to come down to faith, to prove God exists.

But I've come up with an interesting idea:

God punished Isreal (for it's sins) with invading armies, and natural disasters.

So what we could do is, to devise a rating system for cities and countries.

Some criteria could be:
1) Number of believers living there.
2) Proportion of believers to non believers
3) Adherance to God's will (following the Ten Commandments, idol worship, sexual sin, immorality, ect.)

Then, see if there is a correlation between natural disasters, and a lack of faith. Or in other words, do evil cities get punished, and faithfull cities/countries prosper?

What do ya think?