The witty, charming comedy Juno, about an unmarried, pregnant teenager who decides to bear her child, moved into third place in U.S. movie box-office take this past weekend.

In its second week of general release, Juno pulled in an average of nearly $8,500 per screen, significantly more than the healthy $5,376 gathered by National Treasure: Book of Secrets, which was once again the top moneymaker for the weekend. In just three weekends and the intevening weekdays, National Treasure: Book of Secrets has brought in a stunning $171 million in U.S. ticket sales.

I Am Legend held off Juno to finish second on the weekend, earning an estimated $16.4 million to the low-budget, witty comedy’s $16.2 million. The cheerful, funny Alvin and the Chipmunks remained strong at $16 million, finishing fourth.

Also doing very well on a per-screen basis but showing in only a limited number of places and hence low on the charts were the artier films Atonement, There Will Be Blood, and The Bucket List.

The charmning fantasy The Water Horse: Legend of the Deep, is still going strong, finishing eighth, but the gory musical Sweeney Todd, finishing ninth, is doing worse than expected.