These are very embarrassing numbers for Gwen. She should have targeted smaller venues since hype for the album wasn't very huge to begin with. There wasn't much promo surrounding the tour despite her stint on The Voice and publicized relationship with Blake Shelton. Not a lot of people knew about the tour until it was reported on music blogs that it wasn't selling. 16% capacity is insane though. Most artists would have cancelled that date and cited the typical "production issues" just to save face. It would have been better for them as opposed to performing inside empty venues. It has been widely reported over the months that Gwen's tour with Eve was flopping. Only 5,000 tickets had reportedly been sold in a venue that holds 18,000. Her tickets were also sold at largely discounted prices on Groupon, and still couldn't sell.
It's been a decade since Gwen put out a tour-worthy album, and she most likely had to heavily rely on her older hits just to give the tour some legs. I would not have wanted to see Gwen on tour on the basis of that last album alone.
The tour began on July 12th and wraps October 15th.