The Seattle Mariners are a professional baseball team based in Seattle, Washington. The team was established in 1977 as an expansion team and has yet to win a World Series Championship. The Mariners have three American League West division titles and one wild card berth. The team plays their home games at T-Mobile Park, which opened in 1999 and has a retractable roof. The Mariners are known for their innovative use of statistical analysis, which led to the development of the "Moneyball" approach to building a winning team. The team's colors are navy blue, northwest green, and silver, and their logo features a compass rose with an "S" and a baseball diamond.