Your source is counting the share of electricity generation. My source[0] is counting the share of primary energy; including fuel, heating, etc. I believe the latter is more relevant for the current discussion (CO2 emissions and cars). Electricity is not even half of our primary energy use.
Total renewables = 20.1%, that includes hydro which may not be as renewable as we thought.
Just had this discussion but relative to why not re-invest in nuclear so we looked up the amount of nuclear energy (~20%).
Not sure if we are looking at different sources, they are counted differently, etc.
Source for this is; https://www.eia.gov/tools/faqs/faq.php?id=427&t=3