1/3 of download capacity

I am getting 10%-30% of the download capacity of my plan. My plan is for 100 Mbps but when running the test at different times during the day and next to the router, I am not getting more than 30% of my plan. I reset the router, I did the troubleshooting per xfinity step by step and still I am getting the same 30% or less of what my plan offers. The Ping and upload seem OK but the download is quite below of my plan.