Everyone this week should be talking about the past four years.

No, not because of the upcoming presidential election. But because four years ago Saturday was when Lehman Brothers declared bankruptcy, plunging the financial system into sheer chaos and marking the informal beginning of what we now call the Great Recession.

How crazy has it been ever since? Here are 20 numbers that contextualize what we've been through.

308,000 is the drop in local education employment since late 2008. There are fewer local education jobs today than there were in 2004, even though the number of 5- to 18-year-olds has increased by 600,000.

181,000 is the number of times the phrase "economic crisis" was used in news articles from September 2008 through today, according to Google.

828,000 is the decline in the number of Americans age 30 to 44 since 2008. The cohort represents the prime earning, saving, and spending years, and it has fallen every year since 2001.

5 million is the number of personal bankruptcy filings since September 2008. The number of bachelor's degrees awarded from 2008 to 2011 is just slightly more, at 5.2 million.

39.2 is the number of weeks an average unemployed American has been out of work. In September 2008, that figure was 18.7 weeks.

3 million is how many fewer employed Americans there are today compared with September 2008. That's a big improvement from where we've been, though. In late 2010, there were 6.4 million fewer jobs than in 2008.

$3,700 is how much more annual income a median household would have today if incomes had increased by the same annual growth rate from 2008 to 2012 as they did over the previous five decades.

6.4 million is the increase from 2008 to 2011 in the number of Americans the Census Bureau counts as living below the poverty line. Last year, 46.2 million Americans lived below the poverty line.

33.7% is how much the S&P 500 (INDEX: ^GSPC) has returned since the day after Lehman collapsed. That's about 8% a year, or close to stocks' long-term historic average. If you checked the market the before Lehman collapsed and didn't look again until this morning, you'd think the world has been carrying on normally.

41 is the number of days the Dow Jones (INDEX: ^DJI) has gone up or down more than 3.5% since September 2008.

9 is the number of S&P 500 industries, out of 11, that earned higher profits in the past year than in the year before Lehman's collapse. Of the index's 500 components, 345 earned more profit per share last year than they did in 2008.

$32 billion is the net amount of money added to equity mutual funds and ETFs since 2008. That's made up of $316 billion in net withdrawals from equity mutual funds, and $348 billion added to equity ETFs.

$1.2 trillion is the increase in excess reserves banks hold at the Federal Reserve. This is why massive money printing hasn't led to massive inflation -- yet.

1 percentage point is the rise in the unemployment rate for those with a bachelor's degree since 2008. For those with a high school diploma, unemployment has risen by 3 percentage points.

$4.3 trillion is the cumulative gap between potential and actual GDP since late 2008. In other words, had the economy been operating at full capacity, we'd have produced $4.3 trillion more goods and services over the past four years than we actually did.

$9.3 trillion is the increase in aggregate household net worths from 2008 through early 2012. Most of the gain was due to rising stock prices and a big drop in household debt, largely achieved by defaults.

$5.2 trillion is the increase in federal debt since 2008. Interestingly, the annual interest expense on that debt has declined by $30 billion since 2008.

$300 billion is the increase in the amount of student loans outstanding since 2008.

61% is the percentage of new debt issued by the Treasury that the Federal Reserve purchased last year.

Zero is the number of market pundits who said stocks were dead, who said hyperinflation was imminent, or who warned interest rates were about to spike and were right about it.

Of course, Lehman alone isn't responsible for these numbers. The bubble leading up to the 2008 meltdown was years -- even decades -- in the making. Everyone from consumers to governments to central bankers to Wall Street bankers played a role.

But Lehman taught us how quickly and ferociously things can deteriorate when just one bank screws up.

A week after the bankruptcy, former CEO Dick Fuld told congress: "I feel horrible for what has happened to the company and its effects on so many -- my colleagues, my shareholders, creditors, and my clients."

Everyone, it seems, but the innocent victims: the rest of the economy.

Check back every Tuesday and Friday for Morgan Housel's columns on finance and economics.

Fool contributor Morgan Housel doesn't own shares in any of the companies mentioned in this article. Follow him on Twitter, @TMFHousel. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days. The Motley Fool has a disclosure policy.