A hot liquid is to be cooled in a 1-1 shell and tube heat exchanger from 80^oC to 50^oC. Cooling water enters the tube side at 30^oC, and exits at 45^oC. The properties of the liquids are constant. Also, the overall heat transfer coefficient is same for counter-current and co current modes. The percentage saving in heat transfer area for counter-current option with respect to the area of co-current option is __________ (rounded off to third decimal place).