* Sometimes, a graph is easier than reading. My Sun-Times column today is based on a graph I made yesterday afternoon to help myself understand Tuesday’s election. I was so blown away by the chart that I had to write about it. Using exit polling data, here is the partisan makeup of self-identified election day voters since 1992. Click for a better view…

* My column…

For the first time in at least 20 years, more independents voted in Illinois last Tuesday than Republicans.

I spent part of Thursday afternoon going through some exit polling data to see if I could find anything to cheer up my Republican friends. I really couldn’t.

Way back in 1992, when Republican Jim Edgar was governor and George H.W. Bush was running for re-election against Bill Clinton, 39 percent of Illinois voters told the exit pollsters they were Democrats; 34 percent said they were Republicans, and 27 percent said they were independents.

Two years later, when the country turned against Clinton and the Republicans swept just about everything here and nationally, the two parties were tied at 36 percent each in Illinois, with 28 percent saying they were independents.

The Republicans dropped down to 32 percent two years later, while the Democrats surged to 42 percent. Things stayed more or less the same until 2006, George W. Bush’s second midterm election, when Democrats vaulted to 46 percent, Republicans dropped to 31 percent and independents plummeted to a 20-year low of 23 percent.

Obviously, the Democrats won over independents, and the Republicans lost them. Republicans continued losing more independent-minded folks in 2008, when Barack Obama was elected president. Democrats made up 47 percent of the Illinois electoral pool, but Republicans dropped to 28 percent and independents moved up to 28 percent.

And despite a national Republican landslide in 2010, people who said they were Democrats dropped just 3 percentage points, to 44 percent. Republicans moved up only three points to 31 percent, and independents dropped a couple of points to 24 percent.

Believe it or not, the percentage of voters who said they were Democrats was the same in this year’s election as it was in 2008: 44 percent. But Republicans tumbled to 27 percent and independents rose to 28 percent.

The number of people who say they’re independent really hasn’t moved a whole lot over the past two decades. It has been within a five-point range for more than 20 years.

The Republican Party’s problem is that it has been on the decline overall since its 1994 high. Part of the reason is that a triple whammy hit the GOP: George Ryan, George W. Bush and Barack Obama. Ryan’s corruption turned voters away from their favored state governing party; Bush turned Illinoisans off altogether, and Obama is the home-state guy.

So, it’s possible that with both Georges long gone and Obama having won his final election, Republicans might start returning to a more reasonable level of support. But they probably can’t turn around numbers like this on a dime.

For starters, women have left the party in droves. In 1994, 61 percent of Illinois women voted for the pro-choice Edgar’s re-election bid. By 2010, just 44 percent of women voted for the pro-life Republican gubernatorial candidate Bill Brady. And this year, a mere 35 percent of women here voted for Mitt Romney, according to the exit polls.

If the Republicans don’t do something differently, and soon, they’ll hurt their brand so much that most women will eventually refuse to vote for any GOP candidate.

Latinos, the fastest-growing ethnic group in Illinois, also have trended more Democratic. In 2004, 53 percent of Latinos voted for John Kerry. Two years ago, 63 percent of Latinos voted for Democratic Gov. Pat Quinn. This year, 81 percent went with Obama.

The bottom line here is that the GOP has to stop alienating women and Latinos. Now. Today. There is simply no other path back to relevance in Illinois.

* Here’s another graph. This one shows how women have voted over the years…

When Republicans do well with women, they win. End of story.

* Exit polling data…

* 1992

* 1994

* 1996

* 1998

* There was no available exit polling data for 2000 and 2002, but here’s 2004

* 2006

* 2008

* 2010

* And 2012

Discuss.