[Updated and bumped up for discussion purposes.]
The Tribune releases more numbers.
The percentage of Illinois voters who call themselves Democrats is at its highest pre-election level in more than a decade, posing a problem for Republicans trying to win the governor’s mansion and key congressional seats, a Tribune/WGN-TV poll shows.
The poll found 43 percent of voters identified themselves as Democrats while a little more than a quarter of the voters identified themselves as Republicans. The 17 percentage point difference ranks among the most polarized partisan spreads in more than 16 years of Tribune surveys taken prior to an election day. […]
In 1996, 42 percent of Illinois voters identified themselves as Democrats in the October preceding the election while 27 percent aligned with Republicans—a 15 percentage point spread. Clinton ended up winning Illinois in 1996 with 54 percent of the vote and Democrats retook control of the Illinois House from Republicans after a two-year hiatus.[…]
But the most recent Tribune poll found that even in longtime Republican-leaning regions, the GOP no longer might have the upper hand. In the collar counties, 31 percent of voters aligned themselves with Republicans while 29 percent identified with Democrats. Outside the Chicago metropolitan region, voters split equally at 36 percent between Democrats and Republicans.
UPDATE: Yellow Dog Democrat combed through SurveyUSA’s crosstabs to check the percentages of Illinoisans identifying themselves as Democrats and Republicans against the Tribune’s latest poll. This is what he found:
Month - D/R
Feb- 40/25
March - 40/25
April - 42/24
May - 40/30
June - 46/24
July - 43/22
Aug - 45/23