Time of execution IS CHANGES

int main(){
int i=6/3;
printf("%d",i);
return 0;
 }

time of execution in 1st try is 0.02555 sec

time of execution in 2nd try is 0.01755 sec

time of execution in 3rd try is 0.01258 sec

time of execution in 4th try is 0.01276 sec

Please explain how can this happen?