Mortgages are a slog 01 March 2012 5:28PM John Kavanagh The mortgage market continues to slow, with the latest figures showing the annual growth rate slipping below five per cent.According to the Australian Prudential Regulation Authority's latest set of monthly banking statistics, released yesterday, the value of the mortgage books of the lenders in its survey grew by 2.4 per cent over the six months to January - an annualised rate of 4.8 per cent.Total bank mortgages increased by 0.4 per cent in January - also an annualised rate of 4.8 per cent.ANZ and National Australia Bank continue to increase share, Commonwealth Bank has got back above system and Westpac's mortgage business is in the doldrums.Both ANZ and NAB grew their mortgage books by an annualised rate of 9.2 per cent over the past six months - almost double system growth.Commonwealth Bank's mortgage portfolio increased by an annualised rate of 5.2 per cent over the same period and Westpac's book grew at an annualised rate of 0.8 per cent.Other lenders that have increased share over the past six months include Bendigo and Adelaide Bank (up an annualised 7.2 per cent), HSBC (up 5.2 per cent) and Suncorp Bank (up 7.2 per cent).The laggards include AMP Bank (up an annualised four per cent over the past six months), Bank of Queensland (up 3.6 per cent), Citigroup (up two per cent), ING Direct (up 1.8 per cent) and ME Bank (down 1.4 per cent).