The LA Times article references a Pew Center Study. What the study found is that 11% of the households have exited the middle class.
What is interesting is that 7% of them have joined the upper class, while only 4% have sunk into the lower class.
Here is the URL of the study:
http://www.pewsocialtrends.org/2015/12/09/the-american-middle-class-is-losing-ground/
Here are the definitions they use: “In this report, middle-income households are defined as those with an income that is 67% to 200% (two-thirds to double) of the overall median household income, after incomes have been adjusted for household size.7 Lower-income households have incomes less than 67% of the median, and upper-income households have incomes that are more than double the median.”
Plus the lower income group includes a growing population of illegals and uneducated immigrants. I am surprised that the numbers aren’t worse.