XXX testdata are different when I run gen_testdata

created with:
TZ=MST python gen_testdata.py

python --version:
Python 2.7.14

pip freeze:

DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7.
astroid==1.6.5
atomicwrites==1.2.1
attrs==18.2.0
backports.functools-lru-cache==1.5
BTrees==4.5.1
configparser==3.5.0
dateparser==0.7.0
decorator==4.3.0
enum34==1.1.6
filelock==3.0.10
freezegun==0.3.11
funcsigs==1.0.2
futures==3.2.0
gprof2dot==2017.9.19
isort==4.3.4
lazy-object-proxy==1.3.1
mccabe==0.6.1
mock==2.0.0
more-itertools==5.0.0
pathlib2==2.3.3
pbr==5.1.1
persistent==4.4.3
pluggy==0.8.1
py==1.7.0
pyflakes==2.0.0
pygolang==0.0.0.dev6
pylint==1.9.4
pytest==3.10.1
pytest-profiling==1.4.0
python-dateutil==2.7.5
pytz==2018.9
regex==2018.11.22
scandir==1.9.0
singledispatch==3.4.0.3
six==1.12.0
toml==0.10.0
tox==3.7.0
transaction==2.4.0
trollius==2.2
tzlocal==1.5.1
virtualenv==16.2.0
wrapt==1.11.0
zc.lockfile==1.4
ZConfig==3.4.0
zdaemon==4.3
ZEO==5.2.0
-e git+https://github.com/zopefoundation/ZODB@7f5a67b3e0d2dcf2d13f18a42a82e526f6d4055c#egg=ZODB
zodbpickle==1.0.3
-e git+https://lab.nexedi.com/nexedi/zodbtools/@2476850632a7aebd8a74d09cb9128ef7420a4fef#egg=zodbtools
zodburi==2.4.0
zope.interface==4.6.0

zodbtools/test/test_analyze.py

@@ -51,8 +51,8 @@ def test_zodbanalyze(capsys):
     captured = capsys.readouterr()
     assert (
         """Class Name,T.Count,T.Bytes,Pct,AvgSize,C.Count,C.Bytes,O.Count,O.Bytes
-persistent.mapping.PersistentMapping,10,1578,45.633314%,157.800000,1,213,9,1365
-__main__.Object,56,1880,54.366686%,33.571429,9,303,47,1577
+persistent.mapping.PersistentMapping,10,1494,44.279787%,149.400000,1,199,9,1295
+__main__.Object,56,1880,55.720213%,33.571429,9,303,47,1577
 """
         == captured.out
     )