A cross section of web performance over the last two years:
The median top 500 ecommerce home page takes 10 seconds to load. In spring 2012, the median page loaded in 6.8 seconds. This represents a 47% slowdown in just two years.
According to “Retail sites that use a CDN are slower than sites that do not*” on Web Performance Today.
I downloaded the PDF of the report to find out how these measurements were done:
Radware tested the home page of every site in the Alexa Retail 500 nine consecutive times. The system automatically clears the cache between tests. The median test result for each home page was recorded and used in our calculations.
The tests were conducted on March 24, 2014, via the WebPagetest.org server in Dulles, VA, using Chrome 33 on a DSL connection.
I asked about the 2012 settings that were used in the comments section.