Taylor Swift’s “I Knew You Were Trouble.” dips from #2 to #3. The song sold 326K digital copies this week. This is its third week with sales north of 300K. Swift is just the second female artist to top 300K in weekly sales three or more times (as a lead artist). She follows Katy Perry, who achieved the feat with two different hits: “California Gurls” (featuring Snoop Dogg) and “E.T.” (featuring Kanye West). Those songs both topped 300K in weekly sales four times. Will Swift equal that mark next week? Stay tuned.