The middle class is on the decline in every state ... in size, anyway.

The percentage of households considered middle class shrunk nationwide between 2000 and 2013, a state-by-state analysis by Pew Charitable Trusts' Stateline news site found.

Wisconsin had the biggest loss, with the share of middle class households plummeting 5.6 percentage points to 48.9%. In Wyoming, meanwhile, the share of middle class families slipped only 0.3 percentage points to 51.2%.

Related: How has the middle class fared in your state?

Stateline defines the middle class as those making between 67% and 200% of the state's median income. Most states saw median incomes fall between 2000 and 2013, an ominous sign for the well-being of the middle class.

But a smaller middle class is not necessarily a bad thing. It depends on where the former members of this group are going -- up or down the economic ladder.

A separate Pew Research Center study shows that the share of adults in middle-income households has fallen from 61% in 1970 to 51% in 2013.

But many are moving up. The share of upper-income households grew from 14% to 20% in that time period. Low-income households, meanwhile, narrowed from 29% to 25%.