The NCS samples the American population's basic demographic information and product, lifestyle, and media preferences. Data sets are available for 6 months or 12 months (we recommend you use the 12 month study since it has more participants). For the academic version of the product, data is available starting three years ago and going back ten years (so, in 2017 we have access to the studies from 2005 - 2013).
You can access Simmons NCS through Simmons OneView (linked above) or the Business Library's A-Z database list. After you click on the link, you will need to click "Proceed" to get to the search interface.