If you mean that only 5% of the packages on pypi.python.org is Python 3, I would say that sound a bit low. Also unimportant for most, if it's just the correct 5%. There's also a ton of old cruft on pypi.python.org that would count against Python 3, but not really be important to anyone.
Quick check, there are 7633 Python 2 in the package index (https://pypi.python.org/pypi?:action=browse&c=527) and 8949 for Python 3 (https://pypi.python.org/pypi?:action=browse&c=533)