In 1999, 52 years after the first NCAA baseball tournament, a field that started in 1947 with just eight teams and two rounds expanded to 64 teams. And with that expansion came the addition of labeling the eight national seeds.

This season, the 19th of the modern NCAA baseball tournament, those eight seeds were:

1. Oregon State
2. North Carolina
3. Florida
4. LSU
5. Texas Tech
6. TCU
7. Louisville
8. Stanford

And now, as we head to Omaha for the College World Series, only five of those teams remain: Oregon State, Florida, LSU, TCU, and Louisville. They're joined by three unranked squads: Texas A&M, Florida State, and Cal State Fullerton.

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While certainly eye-raising, this isn’t exactly shocking in one of the most unpredictable sports there is. This year, top-seeded Oregon State was the only one of the 293 Division I baseball teams to have single-digit losses, and even they dropped four games on the season.

But exactly how common is it for national seeds to lose before Omaha? And, if they do make it to the College World Series, how do they fair?

To answer that, we looked back at the performance of each national seed for the past 18 years (since they were introduced in 1999):

  Lost in regionals Lost in super regionals Lost in CWS 1st round Lost in CWS 2nd round Lost in CWS semis Lost in CWS finals Won CWS
Total 29 (20.1%) 34 (23.6%) 19 (13.2%) 20 (13.9%) 21 (14.6%) 14 (9.7%) 7 (4.9%)
1 seeds 3 (16.7%) 3 (16.7%) 3 (16.7%) 3 (16.7%) 3 (16.7%) 2 (11.1%) 1 (5.6%)
2 seeds 1 (5.6%) 4 (22.2%) 2 (11.1%) 2 (11.1%) 5 (27.8%) 2 (11.1%) 2 (11.1%)
3 seeds 3 (16.7%) 3 (16.7%) 2 (11.1%) 5 (27.8%) 2 (11.1%) 2 (11.1%) 1 (5.6%)
4 seeds 3 (16.7%) 6 (33.3%) 3 (16.7%) 2 (11.1%) 2 (11.1%) 1 (5.6%) 1 (5.6%)
5 seeds 2 (11.1%) 7 (38.9%) 0 (0.0%) 4 (22.2%) 3 (16.7%) 0 (0.0%) 2 (11.1%)
6 seeds 5 (27.8%) 5 (27.8%) 2 (11.1%) 0 (0.0%) 3 (16.7%) 3 (16.7%) 0 (0.0%)
7 seeds 7 (38.9%) 3 (16.7%) 3 (16.7%) 2 (11.1%) 2 (11.1%) 1 (5.6%) 0 (0.0%)
8 seeds 5 (27.8%) 3 (16.7%) 4 (22.2%) 2 (11.1%) 1 (5.6%) 3 (16.7%) 0 (0.0%)

According to the data, this year’s regionals (where North Carolina, Texas Tech, and Stanford bowed out) were nearly twice as upset-happy than usual. Since 1999, national seeds have lost in the regional 20.14 percent of the time. In other words, approximately 1.6 national seeds fall in the opening weekend each year.

On average, another 1.9 national seeds (23.61 percent) fail to make it out of the super regionals. That leaves 4.5 national seeds (56.25 percent) making it to Omaha for the eight-team College World Series in a standard year, though we saw five survive this year.

Once they get to Omaha, those numbers naturally slim. In the 18-year history of the modern NCAA baseball tournament, 21 national seeds (14.58 percent) have made it to the CWS finals — about 1.2 per tournament. Just seven have ever won the title (4.86 percent), or one every 2.57 years.

(Click to enlarge)

That number has been trending down quite a bit, though. When the national seeds were first introduced, one of the eight ranked teams won the national championship over another ranked team in five straight years (from 1999-2003). In the 13 years since, only two national seeds have won the title — 3-seed LSU in 2009 and 4-seed South Carolina in 2011.

Furthermore, from 1999 to 2006, 65.6 percent of national seeds reached the College World Series. Since then, in the past 10 years, that number shrank to 48.75 percent. In other words, since 2007, less than half of all national seeds even make it to the CWS. This year's total of five national seeds booking trips to Omaha was the highest we've seen since 2011, when six national seeds made the CWS. That was also the last time that a national seed won the championship.

That first year of the national seed was actually the only time a No. 1 seed has ever won the tournament, when Miami took home the crown in 1999. In fact, No. 2 seeds have performed better than the No. 1 seed throughout history. Three top seeds have lost in the regional round, compared to just two No. 2 seeds (including North Carolina this year), more No. 2 seeds have made the CWS semifinals (nine to six) as No. 1 seeds, and No. 2 seeds have captured a pair of titles. 

So, how does all that compare to another popular 64-team tournament? Say, March Madness?

We looked at the performance of the top eight seeds in the NCAA Division I men’s basketball tournament (all No. 1 and No. 2 seeds) since that tournament expanded to its current state in 1985. Though the two tournaments’ formats differ drastically (basketball is single elimination while baseball is a resetting double elimination), for argument’s sake, we compared two tournaments starting at the point at which each has only eight teams left — baseball’s College World Series and basketball’s Elite Eight:

Spots held by top eight seeds in modern NCAA tournament history
  College World Series/Elite Eight Championship Game Champion
Baseball 56.3% 58.3% 38.9%
Basketball 58.0% 68.2% 75.8%

For as crazy as March is known to be, the top eight teams in basketball tend to perform much better than their baseball counterparts.

This year, with five national seeds left in the tournament, the odds for one of them to win the championship are as good as they've been in the past five years. Will one of them break through? Will Oregon State become the first No. 1 seed to win the title since Miami in 1999? Or will one of the three unranked teams — Texas A&M, Florida State, and Cal State Fullerton — make it six straight years of an underdog champion? We shall see.