Looks like we are still on a rocket ship higher. The article you cite misrepresents the math in the title. If the growth rate is lower but the starting number was higher e.g. 323 million, it does not imply the population is in decline, please take a close look at the numbers from the link I sent. 

Imagine if the "growth rate" stayed the same, for example 10% of 100 million people or 10% of 323 million people, I'm very glad it has "decreased" even though the population continues to "increase".

Again another article from those who seek monetary gains on selling more junk, more houses, to more people. Not in our best interest. I hope the US stabilizes around 350 million at MAX and we take excellent care of our country, resources, and each other. 

https://en.wikipedia.org/wiki/Demography_of_the_United_States