> what percentage of them aren't satisfied with the myriad external battery cases and on-the-go-chargers available for smart phones.

Well, from the article, I'd say the answer is around 33%. Specifically, this was in the article:

> Meanwhile, consumers indicated that the new smartphone feature they were most excited about — picked by 33 percent of respondents — was "improved battery life."

Also...

> I challenge the assumption that the majority of people are asking for better batteries.

I don't think anyone said it's a majority. And this article isn't about an assumption, it's about a survey.