Some time this week, Avatar will surpass Titanic to become the best-selling movie in the history of the world. Kind of.

The film's worldwide gross is nearing $1.85 billion, which is more than any movie ever released. But adjusted for inflation, Avatar is not the best selling movie of all time. In fact, *going by domestic spending, it's not even close to the top.

Adjusting for inflation might seem like a wonky buzz-kill to James Cameron's opus, but it's really important. The average ticket price in 1939, when Gone with the Wind hit theaters, was 23 cents. My Avatar ticket cost $10.50. That's 45-times more expensive! As Slate's Zachary Pinkus-Roth noted, this would be comparing somebody's 100-yard sprint time to a 2.22-yard jump.

Here's the full list of the biggest domestic grosses adjusted for inflation from Box Office Mojo (the list does not include Avatar, which has made $560 million):

So inflation-adjusting puts Avatar ahead of Thunderball and just behind, um, Grease. Grease! Wait, can that be right?

It turns out that there are a couple problems with counting all tickets sales and multiplying them all by the inflation index. First, by treating all ticket sales as equal, we overestimate the grosses of movies where a big proportion of the sales were to children, whose tickets cost less. That's one reason why movies like 101 Dalmatians, Fantasia and The Lion King rank so high. Another problem with the list is that the cost of a movie ticket has actually grown faster than the consumer price index, according to Pinkus-Roth. That means that a ticket to Gone in 60 Seconds (2000) cost more in relation to other items than a ticket to Gone with the Wind (1939). And those are just two of the most serious issues.

So this is an imperfect list, but the point it makes is instructive. It's true that Avatar has made more dollars than any movie ever, but it's not entirely accurate to call it the biggest movie of all time.

*Thanks to Charles Davi for making me emphasize that this list is domestic box office. So Avatar's worldwide gross of $1.85 beats Gone with the Wind's domestic gross record.