I disagree, there doesn't seem to be a clear relationship with affluence. Here's the list along with GDP PPP per capita at a country level [1]:

  Helsinki, Finland   11/12   35771
  Mumbai, India        9/12    3843
  Budapest, Hungary    8/12   19497
  New York, US         8/12   51704
  Moscow, Russia       7/12   17518
  Ambsterdam, NL       7/12   41527
  Berlin, DE           6/12   38666
  Ljubljana, Slovenia  6/12   27837
  London, UK           5/12   36569
  Warsaw, PL           5/12   20562
  Bucharest, Romania   4/12   12722
  Rio, Brazil          4/12   11747
  Zurich, Switzerland  4/12   44864
  Prague, CZ           3/12   27000 
  Madrid, Spain        2/12   30058
  Lisbon, Portugal     1/12   23047

n.b. How about 'least honest source of pageviews' for Readers Digest on this article?

1. International Monetary Fund, 2012 data.

Mumbai #2, Zurich #14... That seems out of place as well.