The mortgage market grew at an annualised rate of almost 10 per cent during the first two months of the year, according to housing finance application data analysed by RP Data.RP Data launched its Mortgage Index last month, drawing on its valuation platform to calculate the number of housing finance applications being prepared. The company claims to manage more than 90 per cent of all banking sector valuation instructions.In raw terms, in early March the index hit its highest level since 2009.In seasonally adjusted terms, the index increased from 76.9 to 78.1 over the past eight weeks - an increase of 1.6 per cent, or 9.6 per cent annualised.According to official figures, lenders' mortgage balances grew by around four per cent last year. RP Data said its figures were an indicator of a pick-up of growth in the official figures.