The most recent substantial revision of the election law came in February 2015, and was partially upheld by the Constitutional Court in September 2015. An element of preferential voting was introduced by letting voters choose not only for a list of candidates, but also a single member of the same list. If the percentage of votes for a candidate exceeds 10%, they are elected as if it was an open list system. The list ranking is maintained for those candidates that do not meet this quota.