When looking at car-selling sites like Autotrader, Cars.com, or Carsoup, silver is by far the most common color of used NB for sale. But with the 21st Century 12+ models, I see pretty much all the colors except Toffee Brown. Those seem to be rare.
For fun I tried autotrader again today, this time I got:
We found 9 listings within 100 miles of Flint, MI.
You searched for:
Car Type:All Cars
Make/Model:Volkswagen Beetle
Year Range:2000 - 2005
Price Range:$2,500 - $5,500
Seller Type:All Sellers
Modify Search
4 yellow
2 black
3 silver
I'm surprised there are no greens at all this time

But logically it does stand to reason silver would be the most commonly purchased overall. I'm lucky my best choice at the time was yellow since that is what I wanted. And now that you mention it, counting the variations of blue I have seen more around than I realized.
Yeah, when I was little my older sisters had me yelling "PEANUT!" every time I saw a beetle on the road, now I'm a kooky lifelong beetle watcher. :nblove: