The source report that the article is about has a lot more data and explanations: <a href="http:&#x2F;&#x2F;www.pewsocialtrends.org&#x2F;2016&#x2F;05&#x2F;11&#x2F;americas-shrinking-middle-class-a-close-look-at-changes-within-metropolitan-areas&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.pewsocialtrends.org&#x2F;2016&#x2F;05&#x2F;11&#x2F;americas-shrinking...</a>