http://blog.aheadworks.com/2015/10/ecom ... he-market/

Magento CE decreased slightly (-0.5% compared to May, 2015) and now takes the second position of the chart below. However, Magento EE shows a steady growth and its RGR (Relative Growth Rate) is +10.8%.

Magento CE + Magento EE hold the largest share – 31.04%.
Magento CE + WooCommerce together hold the 50.8% market share.