A hot liquid is to be cooled in a $1-1$ shell and tube heat exchanger from $80^{\circ}C$ to $50^{\circ}C$. Cooling water enters the tube side at $30^{\circ}C$, and exits at $45^{\circ}C$. 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).