According to the NPD group, one of the more well known market research groups and one that is used by many big companies, all areas of gaming in America are in decline. The only exceptions currently seem to be mobile and online gaming. Their market research shows that at least 2/3 of the country is still playing video games but 5% of population have dropped the pastime since 2011. See the source for more info.
Source (gamasutra)
NPD survey direct link (only a basic summary is available without NPD subscription)