A person deposited Rs. 80,000 in a co-operative limited for 2 years to get the yearly compound interest at the rate of 15% per annum after deducting the 5% tax on the interest. But right after a year, the bank has changed the policy and decided to compute the interest half yearly at the same rate of interest. After deducting tax, by what percentage does the interest of the first year differ from the interest of the second year?