Nah. The term is "middle class" where class is defined by the lifestyle/societal-position on a class ladder, not some statistic mean regarding income.
You can have societies with 90%+ population in low class or 50% population in middle class.
History buffs generally know more how it looks for a society to have various levels of classes. I wish we all looked at history more, especially myself if I only had the time to stop rat racing...
