Yeah, that Google Insights data is really only used by marketers. If you're selling a product, those numbers can be useful.
In reality, this is who visits the site (the top 30 this month, anyway):
36.46% US Commercial (.com)
26.74% Network (.net)
13.44% Unresolved/Unknown
2.27% Russian Federation
1.52% Germany
1.38% US Educational (.edu)
1.34% Brazil
1.23% Netherlands
1.17% Australia
1.10% Canada
1.01% United States (.us)
0.85% Greece
0.79% Sweden
0.78% Italy
0.72% United Kingdom
0.71% Denmark
0.66% Mexico
0.65% Poland
0.58% Austria
0.55% France
0.47% Argentina
0.46% Non-Profit Organization (.org)
0.42% Norway
0.34% Romania
0.31% Portugal
0.30% Finland
0.27% India
0.25% Japan
0.24% Hungary
0.22% Croatia (Hrvatska)
But of course even those stats are a little skewed, because .com, .net and .org can come from any country.