The revival of viticulture in the British Isles, mainly in England, but also Wales (and even Scotland), that began in the mid 20th century has matured into a small but significant industry with a planted area in 2013 of 1,884 ha/4,655 acres, of which 1,571 ha/3,882 acres were already producing wine. Average annual production was around 3 million bottles. While initially English wines were often thin and acidic, climate change has led to a revolution in the vine varieties grown and in quality in wine. This is especially true of the bottle-fermented sparkling wines which are increasingly being compared to champagne. English and Welsh wine is subject to eu winemaking regulations and is made strictly from freshly picked, UK-grown grapes (see british made wine).