A new poll released by Rasmussen Reports shows U.S. Rep. Mark Kirk holding a marginal edge over State Treasurer Alexi Giannoulias in the race for U.S. Senate. Only 4 percent of those surveyed favored Green Party candidate LeAlan Jones while 8 percent remained undecided.

Here are the topline results from the survey (with the results of the four previous Rasmussen polls in parentheses):

Kirk: 44% (41%, 40%, 40%, 39%)
Giannoulias: 41% (37%, 42%, 40%, 40%)

Rasmussen still characterizes this race as a "toss-up." Nate Silver at FiveThirtyEight gives Kirk a 55 percent chance of winning. You can check out TPM's polltracker for the race here.