The 21st century held such promise for Georgia’s middle class.

It rode a big wave of prosperity at the close of the 20th century. That wave began to crash soon afterward.

We base this assertion on a statistic called real median household income. That would be the figure – adjusted for inflation – that falls exactly in the middle. Half of all household incomes are above it and half below. What could be more middle-class?

In the final decade of the 20th century, Georgia saw its real median household income swell 24.87 percent. It started in 1991 at $45,389, and it rose to $56,680 by 2000.

In that time, it also jumped from 36th out of the 50 states and the District of Columbia to 24th.

More importantly, Georgia’s middle class also nearly closed the gap with the nation’s middle class. In 1991, the state’s real median household income was a fraction more than 90 percent of the national figure of $50,249. (In other words, Georgia’s middle class earned about 90 cents for every dollar taken in by its counterpart at the national level.) By 2000, Georgia was at $56,680, almost on par with the national real median household income of $56,800. The difference comes out to $10 per month.

Shortly after that, things took a turn for the worse.

It’s true that thanks to two recessions – one in 2001 and the Great Recession of 2008 and 2009 – most Americans went through hard times. The real median household income for the nation, according to the Federal Reserve Bank of St. Louis, dropped from $56,800 in 2000 to $51,939 in 2013. That’s a decline of 8.55 percent.

Georgia did much worse, seeing a drop of 16.3 percent, to $47,439. Its middle class was now taking in a fraction more than 91 percent of its counterpart on the national level, or 91 cents on that dollar.

Nearly all the gains of the 1990s had been given back.

That’s not to say there weren’t some good years. In 2006, with a real median household income of $57,010, Georgia exceeded the national average. The Peach State’s middle class was making $1.02 for every dollar earned by the middle class at the national level.

That just made the decline seem all the steeper.

Since 2000, only seven states have seen larger losses by percentage. Some of those states are familiar stories by now. Nevada saw its housing market vanish somewhere into Area 51. It also experienced the biggest drop, 26.7 percent.

Michigan (a decline of 20.73 percent) and Ohio (down 20.16 percent) were almost totaled by troubles in the auto industry.

Some of those states, though, could at least content themselves by knowing they’re still above the national average. Minnesota saw a decline of 17 percent, but with a real median household income of $60,907, it still ranked 10th overall in 2013.

Here’s a look at the 10 states that saw the biggest such declines by percentage, with their real median household income in parentheses:

Kentucky ($42,158), down 14.06 percent

Alaska ($61,137), down 14.47 percent

Georgia ($47,439), down 16.3 percent

Minnesota ($60,907), down 17 percent

Missouri ($50,311), down 17.52 percent

Ohio ($46,398), down 20.16 percent

North Carolina ($41,208), down 20.49 percent

Michigan ($48,801), down 20.73 percent

Delaware ($52,219), down 23.35 percent

Nevada ($45,369), down 26.7 percent

Georgia also watched a large majority of the South, as defined by the U.S. Census Bureau – which is the only way to explain why Delaware is in the South – improve its position relative to the Peach State.

Here’s a look at how the region broke down in terms of real median household income in 2013 with the national ranks for each locality:

3. Virginia — $67,620

4. Maryland — $65,262

11. District of Columbia — $60,675

26. Texas — $53,027

28. Delaware — $52,219

36. Florida — $47,886

37. Georgia — $47,439

41. Oklahoma — $43,777

42. South Carolina — $43,749

43. Tennessee — $42,499

44. Kentucky — $42,158

46. Alabama — $41,381

47. North Carolina — $41,208

48. Mississippi — $40,850

49. West Virginia — $40,241

50. Arkansas — $39,919

51. Louisiana — $39,622

Now, here’s a look at how those same localities performed in terms of percentage gains or losses from 2000 to 2013:

2. District of Columbia, up 8.81 percent

4. Virginia, up 5.99 percent

11. West Virginia, up 1.14 percent

12. Texas, up 0.89 percent

14. Oklahoma, down 0.21 percent

18. Arkansas, down 0.62 percent

24. Louisiana, down 4.64 percent

29. Tennessee, down 7.85 percent

32. Florida, down 8.89 percent

37. Maryland, 11.53 percent

39. Mississippi, down 11.95 percent

40. Alabama, down 13.64 percent

41. South Carolina, down 13.91 percent

42. Kentucky, down 14.06 percent

44. Georgia, down 16.3 percent

48. North Carolina, down 20.49 percent

50. Delaware, down 23.35 percent

The gains were big enough, or the losses small enough, that the District of Columbia, Texas and Florida all passed Georgia in real median household income between 2000 and 2013.

In all, the District of Columbia and seven Southern states – nearly half the region’s localities – outperformed the nation in the percentage change of real median household income. That means, in one sense, that the neighborhood got a little richer while Georgia’s middle class got poorer.