The Sainte-Laguë method is used for allocating parliamentary seats to parties. As a result, the percentage of representatives is roughly equal to the nationwide percentage of votes. Still, a party with a high number of votes in only one constituency can win a seat there even if the nationwide percentage is low. This has happened several times in Norwegian history. Conversely, if a party's initial representation in Stortinget is proportionally less than its share of votes, the party may seat more representatives through leveling seats, provided that the nationwide percentage is above the election threshold, currently at 4%. In 2009, nineteen seats were allocated via the leveling system. Elections are held each four years (in odd-numbered years occurring after a year evenly divisible by four), normally on the second Monday of September.