You may or may not be interested in The White House’s Council of Economic Advisers take on the digital divide in the United States but their report issued this summer, Mapping the Digital Divide (July 2015), provides a fair amount of data on internet penetration and demographics.
From the Introduction:
This report examines the state of the digital divide using new data from the Census’ 2013 American Community Survey (ACS), which we link with the most recent version of the National Broadband Map (NBM). The large scale of the ACS allows us to examine Internet use at a level of granularity that was not previously possible. Our most important findings illustrate how the digital divide reflects factors that influence the demand for Internet, such as household income, and also the costs of providing it (e.g. population density). Although we consider several potential explanations for the digital divide, our main goal is not to measure the causal impact of any particular factor, but rather to characterize disparities in Internet access and adoption as they exist today. Overall, the evidence shows that we have made progress, with the largest gains occurring for those groups that started with the least. While this suggests the beginning of convergence toward uniformly high levels of access and adoption, there is still a substantial distance to go, particularly in our poorest neighborhoods and most rural communities, to ensure that all Americans can take advantage of the opportunities created by recent advances in computing and communications technology.