The majority (80 per cent) of Württemberg's wines are red, making it the biggest producer of red wine in Germany. A large part (71 per cent) of the area under vine is situated on slopes or steep hillsides, some of which have a 20 per cent gradient, making it more difficult to cultivate. Just under 15,000 winegrowing families organised into cooperatives are responsible for cultivating 75 per cent of the vineyards. Württemberg is characterised by a particularly broad range of grape varieties and is one of the few places where lemberger and trollinger are grown. Many of the new varieties that have become important to German winegrowing such as dornfelder come from Württemberg.