100000: 446368.754 inserts/sec, 1050330.051 lookups/sec
    200000: 424977.633 inserts/sec, 821176.759 lookups/sec
    400000: 398651.394 inserts/sec, 805369.896 lookups/sec
    800000: 399463.754 inserts/sec, 787853.768 lookups/sec
   1600000: 390381.775 inserts/sec, 766870.015 lookups/sec
   3200000: 377860.715 inserts/sec, 720909.739 lookups/sec