Liveness tracing prints liveness of the regions in the group as a percentage. The printed value is just the integer part of the calculated value.

Eg.

```
50.707s][trace][gc,liveness] GC(13) ### groud-id num-regions gc-eff liveness remset type
50.707s][trace][gc,liveness] GC(13) ### (bytes/ms) % (bytes)
50.707s][trace][gc,liveness] GC(13) ### 1 70 0.0 100 3199208 Y
50.707s][trace][gc,liveness] GC(13) ### 2 51 5298129.5 18 1224072 M
50.707s][trace][gc,liveness] GC(13) ### 3 5 3223983.6 31 176648 M
50.707s][trace][gc,liveness] GC(13) ### 4 5 3022016.3 32 176648 M
50.707s][trace][gc,liveness] GC(13) ### 5 5 2819254.5 34 179528 M
50.707s][trace][gc,liveness] GC(13) ### 6 5 2772982.1 35 175528 M
50.707s][trace][gc,liveness] GC(13) ### 7 5 2570886.0 36 176648 M
50.707s][trace][gc,liveness] GC(13) ### 8 5 2531264.8 37 176648 M
50.707s][trace][gc,liveness] GC(13) ### 10 5 2487867.1 38 179528 M
50.707s][trace][gc,liveness] GC(13) ### 9 5 2460288.9 38 176648 M
50.707s][trace][gc,liveness] GC(13) ### 11 5 2248934.0 41 176648 M
50.707s][trace][gc,liveness] GC(13) ### 12 5 2172906.7 42 216424 M

```
A few more significant digits would be nice.