Related material, number of modules and average growth/day by [http://www.modulecounts.com/]
count | avg/dayJava..........114,860.|.108/day.[MAVEN]
Ruby.........106,195.|..50/day.[Rubygems]
Go..............86,512.|.299/day.[GoDoc]
PHP.............68,276.|..99/day.[Packagist + Pear]
Python.........64,865.|..56/day.[PyPI]
Modulecounts offers info for more languages, I just did a TL;DR
EDIT: is there a good way to present data on HN?