From a quick search online I see no reason why you distantiate what you describe from [auditory hallucinations](https://en.wikipedia.org/wiki/Auditory_hallucination#Individual_accounts):

> a form of hallucination that involves perceiving sounds without
> auditory stimulus.

Given [the article you link to](http://www.intervoiceonline.org/2298/voices/positive-voices/hearing-voices-amongst-normal-people.html), which arguably _does_ address your question (yes, some people report experiencing this), you mainly seem to be concerned that this unequivocally would be considered a mental illness. However, judging from the Wikipedia article (and its subheading ['Non-disease associated causes'](https://en.wikipedia.org/wiki/Auditory_hallucination#Non-disease_associated_causes)) this is seemingly not the case.

> However, individuals may hear voices without suffering from
> diagnosable mental illness. ([Thompson, 2006][1])

[The article by Thompson][1] mentions a study for which unfortunately no source is provided, thus I would take the following with a grain of salt:

> But studies by Dutch researchers that began in the 1990s found that
> some healthy people also regularly hear voices. ... Many of the people
> who contacted them did not find the voices disruptive and had never
> felt the need to consult mental health services. ... The resulting
> studies found that more people might hear voices than psychologists
> had thought, perhaps around 4 percent of the population.

It might, however, set you on the right path to finding the actual studies, or more recent work in regards to how many people report hearing voices not attributed to the self without considering them as a mental illness.

<sub>
Thompson, Andrea (September 15, 2006). ["Hearing Voices: Some People Like It"](http://www.livescience.com/7177-hearing-voices-people.html). LiveScience.com.
</sub>


  [1]: http://www.livescience.com/7177-hearing-voices-people.html