A flocculator tank has a volume of 2800 m3. The temperature of water in the tank is 15°C, and the average velocity gradient maintained in the tank is 100/s. The temperature of water is reduced to 5°C, but all other operating conditions including the power input are maintained as the same. The decrease in the average velocity gradient (in %) due to the reduction in water temperature is ________ (round off to nearest integer).

[Consider dynamic viscosity of water at 15°C and 5°C as 1.139 × 10-3 N - s/m2 and 1.518 × 10-3 N - s/m2 , respectively]