A fluorine disposal plant was constructed to carry out the following reactions.
  $2F_2+4NaOH\to 4NaF+2H_{2}O+O_2$
 $2NaF+CaO+H_{2}O\to Ca{F}_2+2NaOH$
As the plant operated, excess lime was added to bring about complete precipitation of the fluorides as $Ca{F}_2$  . Over a period of operation, 1900 kg of fluorine was fed into the plant and 10,000 kg of lime was required. What was the percentage utilization of lime? (Ca = 40, F= 19)