It has been a long time since a Swiss man exceeded 8000 points for decathlon. It was in 2003, to be exact, when Rolf Schläfli achieved 8019 in Götzis and became only the 5th man ever over 8000.
In 1988, Külvet surpassed his best decathlon with a score of 8506 points in Staiki, Belarus. This achievement placed him second in the world that season, just behind Christian Plaziat of France.