According to Box Office Mojo, yesterday Avatar earned another $18.4 million at the US/Canada box office. After 13 days out, the total domestic gross of James Cameron's sci-fi epic now stands at $268.9m. Avatar is officially the top December opener ever (having surpassed Will Smith's I Am Legend) and it's the sixth biggest grosser of 2009, following Michael Bay's Transformers: Revenge of the Fallen ($402.1m), the Daniel Radcliffe franchise Harry Potter and the Half-Blood Prince, Pete Docter's Up, the Robert Pattinson-Kristen Stewart-Taylor Lautner vehicle The Twilight Saga: New Moon, and The Hangover ($277.3m), starring Bradley Cooper.
Internationally, Avatar earned $36.9m on Wednesday, for a total of $525.3m. Approximately two-thirds of the film's overall revenue has come from overseas. Worldwide cume to date (Wed.): $794.2m.
The Best Wednesday in December record, however, still belongs to Peter Jackson's The Lord of the Rings: The Return of the King ($34.4m on Day 1 in 2003), followed by The Lord of the Rings: The Two Towers ($26.1m on Day 1 in 2002), and Alvin and the Chipmunks: The Squeakquel ($18.8m on Day 1 last week).
As per the Box Office Mojo chart, also doing quite well this past Wednesday were Alvin and the Chipmunks: The Squeakquel ($11.7m); the Guy Ritchie-directed Sherlock Holmes ($9.7m), starring Robert Downey Jr and Jude Law; and the Meryl Streep-Alec Baldwin-Steve Martin vehicle It's Complicated ($4.4m).
Five other films made more than $1 million at the box office: Disney's animated The Princess and the Frog ($3.3m), the Sandra Bullock drama The Blind Side (above, $3.2m, total $192.9m), the George Clooney comedy-drama Up in the Air ($2.3m), Rob Marshall's all-star Nine ($1m), and, still holding strong, The Twilight Saga: New Moon ($1m, total of $283.8m).
Nine is the biggest disappointment of the bunch. Poor reviews certainly didn't help this film adaptation of the Broadway musical, itself a musicalized adaptation of Federico Fellini's 8½. Nine, which stars Daniel Day-Lewis, Penelope Cruz, Marion Cotillard, Nicole Kidman, Kate Hudson, Sophia Loren, and Fergie, has grossed a paltry $9m thus far. If the film manages to win a Golden Globe for best comedy or musical (not that likely) or if it gets many Oscar nominations (that's possible), box-office returns may get a boost in early 2010.
According to Paul Dergarabedian (via Deadline Hollywood), domestic attendance figures for 2009 are the highest in five years, with 1.42 billion tickets sold in the United States/Canada at an average price of $7.46.
Photos: Avatar (WETA / 20th Century Fox); The Blind Side (Ralph Nelson / Warner Bros.)

I am pretty sure Avatar has to beat Titanic and Return of the King to become the highest grossing December movie.