This is a great question - and great news - there is an app for that!!

Well, at least there is a web site.

Based on millions of recent test results from Speedtest.net, there is an index that compares and ranks consumer download speeds around the globe. Also plotted is the value is the rolling mean throughput in Mbps over the past 30 days where the mean distance between the client and the server is less than 300 miles.  The following screenshot is from the web site called Net Index by Ookla.

Who has the fastest Internet?  The US does not even make the top 10!