Don't have an actual figure,but this may help.
http://www.lga.gov.uk/lga/core/page.do?pageId= 45267
Trees and shrubs grown too close to homes are responsible for almost 70 per cent of subsidence. The thirstiest trees include eucalyptus, oak, Leylandii cypress, poplar and willow.
http://www.telegraph.co.uk/gardening/main.jhtm l?xml=/gardening/2002/11/30/gboxes.xml
The drink problem
Some trees are bigger drinkers than others. A fully grown apple tree can drink 4,400 gallons of water per year; a mature poplar draws up 12,000 gallons. When a tree is vigorous and growing it can drink even more. Clay soil shrinks when it is dessicated by a heavy drinker and the higher the plasticity (the smaller the particles in the clay) the more it shrinks.
The biggest drinkers
Poplar, willow, oak, eucalyptus and leylandii.