CHART: Netflix Is Slowly Destroying HBO's Customer Base

Netflix appears to be killing HBO and its brethren in premium cable TV, according to new data from NPD Group, the big market research company.

The proportion of people subscribing to streaming video on demand services is now almost equal to the number of people who get premium cable TV channels like HBO and Showtime, NPD says.

Streaming video customers are 27% of the TV audience, and premium cable subscribers are now 32%, NPD says. In the last 18 months, the premium cable market share has declined by six percentage points while the streaming video folks have increased by four points.

If NPD's numbers are right, it means 15% of HBO's customer base just disappeared in the last few months.

NPD analyst Russ Crupnick told Variety he believed consumers are eliminating their premium-TV subscriptions in favor of Netflix, Roku, Aereo and other web video streaming services.

Netflix had 31.1 million U.S. streaming subscribers in Q3 2012, up 24% from the prior year.