Last week, the United States Soccer team jumped to No. 6 in the monthly FIFA World Rankings, its highest mark since the rankings were introduced in 1993.

In the rankings released June 5, the U.S. checked in at 10th, but a month later it vaulted past international powers France, England and Portugal into sixth.

So just how did the U.S. National Team vault so high?

It's a complicated formula that factors in results from the past eight years, and puts the complexities of college football's BCS to shame.

The FIFA World Rankings incorporate 205 national teams across the globe from No. 1 Brazil to No. 205 American Samoa.

All matches from friendlies to World Cup matches are factored in, and they date back eight years. That's right, the United States' terrible showing in the 1998 World Cup still negatively affects the U.S. rankings, but each year in the past seven years its impact has diminished by one-eighth.

In addition to the type of match — because World Cup matches carry more weight than friendlies — five other criteria factor into the monthly rankings: wins, losses and ties; number of goals; home or away match; importance of match; regional strength.

According to the FIFA Web site, only the seven best results per year are given full weighting. Results from the past are given progressively less weighting year by year until after eight years they are dropped completely. In this way current success is rated more highly than past results.

Here's a more specific breakdown of the criteria taken from the league Web site:

Wins, losses & ties

Naturally a win will bring more points than a defeat in any system, but simply giving two or three points for a win, one for a draw and none for a defeat, would not fully meet all the requirements for a reliable world-wide ranking system.

Therefore the distribution of points also takes into consideration the relative strengths of the two teams. In practice this means that a win over a weaker opponent will earn fewer points than victory over an equally rated or stronger one. It is also possible for a weak team that puts up a good show against a stronger one to earn points in defeat — though as a general rule not as many as the stronger team that beat them.

Number of goals

A further factor taken into consideration is the number of goals scored and conceded in a match. Here, too, the distribution of these points depends on the relative strengths of the two teams. In other words, a goal scored by the lower-rated team will be weighted more than one scored by the higher-rated side. On the other side of the balance sheet, points are deducted for goals conceded. To encourage attacking football with more goals, goals conceded are weighted less than goals scored. In matches decided on penalties, only goals scored during regular playing time or extra time are considered in the calculation.