The data is in, and we’re ready to declare the top 15 newspaper websites of 2008! It was a hard-fought battle in a year that saw visitors to all newspaper sites rise by 12.1 percent from the year prior. We’ve ranked the top 15 by average monthly unique visitors, according to Nielsen Online, which is the source of all our data (via Editor & Publisher‘s monthly reports). Analysis, charts, and fancy interactive graphics will follow later today and tomorrow, but first, let’s see the list:

1. The New York Times
19,503,667 average monthly uniques
Increase of 33% from 2007
Peak month: 21,340,000 uniques in March [Eliot Spitzer]

2. USA Today
10,845,000 average monthly uniques
Increase of 12% from 2007
Peak month: 12,314,000 uniques in January

3. The Washington Post
10,260,167 average monthly uniques
Increase of 19% from 2007
Peak month: 12,956,000 uniques in September

4. The Los Angeles Times
7,886,250 average monthly uniques
Increase of 54% from 2007
Peak month: 11,136,000 uniques in November

5. The Wall Street Journal
7,169,333 average monthly uniques
Increase of 60% from 2007
Peak month: 9,047,000 uniques in September [Lehman Bros.]

6. The Boston Globe
5,211,083 average monthly uniques
Increase of 22% from 2007
Peak month: 8,610,000 uniques in September [Red Sox]

7. New York Post
4,335,583 average monthly uniques
Increase of 30% from 2007
Peak month: 5,000,000 uniques in October

8. Chicago Tribune
4,271,833 average monthly uniques
Increase of 34% from 2007
Peak month: 5,235,000 uniques in December [Blagojevich]

9. New York Daily News
4,226,083 average monthly uniques
Increase of 68% from 2007
Peak month: 5,888,000 uniques in November

10. San Francisco Chronicle
4,158,000 average monthly uniques
Increase of 10% from 2007
Peak month: 5,129,000 uniques in September

11. Newsday
3,163,000 average monthly uniques
Increase of 7% from 2007
Peak month: 3,911,000 uniques in February

12. Politico
3,113,000 average monthly uniques
Increase of 132% from 2007
Peak month: 4,565,000 uniques in October

13. Chicago Sun-Times
2,884,417 average monthly uniques
Increase of 26% from 2007
Peak month: 3,982,000 uniques in October

14. The Houston Chronicle
2,808,750 average monthly uniques
Decrease of 10% from 2007
Peak month: 3,414,000 uniques in May

15. The Dallas Morning News
2,647,500 average monthly uniques
Increase of 52% from 2007
Peak month: 3,777,000 uniques in September

A few quick notes: We’re only looking at the websites of news organizations that also print a newspaper here, because they face a special challenge in transitioning from print to the web. And while it seems clear that increasing traffic alone won’t solve the business problems of newspapers, it’s all they’ve got right now. (For comparison, here’s a top-30 ranking of all news sites in December.) Politico makes our list because it distributes a small-circulation print edition when Congress is in session. Also keep in mind that Nielsen’s web stats, like its television ratings, are frequently disputed estimates that may be more valid in relative terms such as comparing a site’s traffic to its competitors. Fortunately, that’s what we’re doing here. And finally, we’re looking at monthly unique visitors, which advertisers prefer, while ignoring time spent per visitor because that data is all over the place and difficult to compare.

In another post, we take a closer look at patterns among the five national newspapers that top the list. Tomorrow, we’ll do the same for the regional newspaper sites.

[Hello, readers from Romenesko and elsewhere, and welcome to the Nieman Journalism Lab. We’re trying to figure out the future of journalism online — what business models will support it, how journalists’ jobs will be changing, and how good work can be best be done in our changing environment. Check out the rest of the site; you might want to follow us on Twitter or subscribe to our RSS feed.]