better indicator for middle class

here from CIA

I don't pretend to understand what a Lorenz curve is, but let's just look at the rankings.

here is the entry site:
https://www.cia.gov/library/publications/the-world-factbook/fields/2172.html

"If income were distributed with perfect equality, the Lorenz curve would coincide with the 45 degree line and the index would be zero; if income were distributed with perfect inequality, the Lorenz curve would coincide with the horizontal axis and the right vertical axis and the index would be 100."

here is the index rankings:
https://www.cia.gov/library/publications/the-world-factbook/rankorder/2172rank.html

enjoy.

1. Nambia, 70.7 (2003)
lots of African countries
...

43. USA, 45 (2007)
...

74. Japan, 38.1 (2002)

102 Spain, 32.0 (2005)

104. Italy, 32 (2006)

123. Germany, 27 (2006)