rate; 10 kHz digital-only bandwidth confined to ±5 kHz of the channel center allows 12–35 kbit/s; 20 kHz digital-only bandwidth using ±10 kHz (including half of the adjacent channels) allows 24–72 kbit/s. DRM+, a different system based upon the same principles, operates in the VHF band with 100 kHz digital-only bandwidth which allows 700 kbit/s data rate. Actual DRM bit rates vary depending on day versus night transmission (groundwave versus skywave) and the amount of bits dedicated for error correction (signal robustness). Although DRM offers a growth path for AM broadcasters, unfortunately it shares many of the same flaws as DAB and HD AM: Shorter broadcast distance in hybrid mode compared to an analog AM signal Poor reception inside vehicles and buildings Interference with adjacent channels when using the 20 kHz mode though in all-digital mode the signal fits inside the designated channel mask. Digital Radio Mondiale is an open standards system, albeit one that is subject to patents and licensing. HD Radio is based upon the intellectual property of iBiquity Digital Co. / Xperi Holding Co. The United States uses DRM for HF / shortwave broadcasts. Acceptance and criticism Awareness and coverage According to a survey dated 8 August 2007 by Bridge Ratings, when asked the question, "Would you buy an HD Radio in the next two months?" Only 1.0% responded "yes". Some broadcast engineers have expressed concern over the new HD system. A survey conducted in September 2008 saw a small percentage of participants that confused HD Radio with satellite radio. Many first-generation HD Radios had insensitive receivers, which caused issues with sound quality. The HD Radio digital signal level is 10–20 dB below the analog signal power of the station's transmitter. In addition, commentators have noted that the analog section of some receivers were inferior compared to older, analog-only models. However, since 2012, HD capable receiver adoption has significantly increased in most newer cars, and several aftermarket radio systems both for vehicles and home use contain HD Radio receivers and special features such as Full Artist Experience. iBiquity reports that 78% of all radio listening is done on stations that broadcast in HD. There are an increasing number of stations switching to HD or adding subchannels compatible with digital radio, such as St. Cloud, Minnesota, where many local radio outlets find a growing number of listeners tuning in to their HD signals, which in turn has benefited