Monza, Italy:Seven times world champion Michael Schumacher of Germany has announced his retirement. The announcement came right after he won the Italian Grand Prix at Monza, his sixth win this season. The victory puts him two points behind current championship leader Fernando Alonso who crashed out of the race because of engine trouble. Kimi Raikkonen came second. The title at Monza was also Schumacher's 90th win of his Formula One career.