Question

Why is mexico called a developing country

Answer 1

Here is a good defintion
http://en.wikipedia.org/wiki/Developing_country

Answer 2

The first site explains that there are no hard and fast rules for determining what is a developing country. It seems to me that Mexico falls just short of developed.

Check the second site for Mexico's statistics.

http://en.wikipedia.org/wiki/Developing_country

https://www.cia.gov/library/publications/the-world-factbook/index.html