HALIFAX, England, March 28, 2013 /PRNewswire/ -- Just 15% of 2012/13 ISA customers have used full allowance The average cash ISA balance across England and Wales is £8,844, according to Halifax; equivalent to a third (33%) of national average pre-tax annual earnings  of £27,039. There are significant differences in average ISA balances depending on age, location and gender. Savers aged 25 to 34 have an average balance of £2,712, which is less than half of the current annual Cash ISA allowance of £5,640. The average balance increases to £4,389 for those aged between 35 and 44 and again to £7,330 for customers between 45 and 54 years of age; all well below the national average. Unsurprisingly, older savers have higher balances. Those in the 55 to 64 age band have an average balance of £11,809, which is a third above the national average; rising to £15,035 for savers over the age of 75 (See Table 1). Indeed, industry  figures show that the proportion of savers with ISAs valued at £15,000 or more is highest among the 65 plus age group. Richard Fearon, Head of Halifax Savings, comments: "Our research shows that age is a significant factor in determining the size of an ISA holding. Older savers, not surprisingly, have the highest ISA balances as they have had longer to accumulate savings whereas savers between 25 and 54 have an ISA balance considerably lower than the national average. "Savers aged between 25 and 54 make up over 70% of all taxpayers and, therefore have the greatest chance to benefit from using their full ISA allowance. Just 15% of savers that have funded their ISA with us this year have reached the maximum limit, so the potential for further tax free saving over the next month is huge."