x drop/merge-timings.txt
+ keep/merge-timings.txt
+------------------------------------------------------------------------+
| +                                                                      |
| +                                                                      |
| +                                                                      |
| +                                                                      |
| +                                                                      |
| +                                                                      |
| +                                                                      |
| +                                                                      |
| +                                                                      |
|++                                                                x     |
|++                                                                x     |
|++                                                                x     |
|++                                                                x     |
|++                                                               xx     |
|++                                                               xx     |
|++                                                            x  xx     |
|++                                                            x  xx     |
|++                                                            x  xx     |
|++                                                            x  xx     |
|++                                                            x  xx     |
|++                                                            x  xx     |
|++ +                                                          x  xx     |
|++ +                                                          x  xx x   |
|++ +                                                          x  xx x   |
|++++                                                          x  xxxx   |
|++++                                                          xx xxxxx x|
||A|                                                            |_AM|    |
+------------------------------------------------------------------------+
    N           Min           Max        Median           Avg        Stddev
x  50      1.337052      1.406142     1.3663635     1.3634524   0.015210835
+  50      0.889559      0.913354     0.8943785    0.89644634  0.0056274351
Difference at 95.0% confidence
	-0.467006 +/- 0.00455057
	-34.2517% +/- 0.333753%
	(Student's t, pooled s = 0.0114682)