From Variety.com: "And at CW, "Supernatural" (1.3/3 in 18-49, 3.2 million viewers overall) matched its season high in adults 18-34 (1.4/4)."
From TVGuide.com: "The chances of Supernatural seeing a fourth season just got a little brighter. Last night's zombie-themed episode scared up some serious ratings, with the show matching its best performance of the season in adults 18-34 and women 18-34, and scored a season high with men 18-34. It also attracted its largest audience of the season (3.22 million). And get this: It did so on a night when Smallville wasn't even on. A Supernatural rerun aired at 8 pm. Crazy, right? — Michael Ausiello"