Los Angeles ? James Cameron’s “Avatar” is on a course to sink “Titanic” at the box office.

No. 1 for the sixth-straight weekend with $36 million, the 20th Century Fox sci-fi spectacle lifted its domestic total to $552.8 million, according to studio estimates Sunday. “Avatar” raised its worldwide total to $1.841 billion. That’s $2 million shy of first place behind Cameron’s last movie, the 1997 shipwreck epic “Titanic,” at $1.843 billion.

Screen Gems’ apocalyptic thriller “Legion,” featuring Paul Bettany as an Armageddon-fighting fallen angel, debuted behind “Avatar” at No. 2 with $18.2 million.

Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Hollywood .com.

1. “Avatar,” $36 million.

2. “Legion,” $18.2 million.

3. “The Book of Eli,” $17 million.

4. “Tooth Fairy,” $14.5 million.

5. “The Lovely Bones,” $8.8 million.

6. “Sherlock Holmes,” $7.1 million.

7. “Extraordinary Measures,” $7 million.

8. “Alvin and the Chipmunks: The Squeakquel,” $6.5 million.

9. “It’s Complicated,” $6.2 million.

10. “The Spy Next Door,” $4.8 million.