Google has made significant updates to its knowledge graph in recent times. Its developer conference being where the most significant changes such as a smarter voice search were revealed.
Now it's brought another new feature into its mobile voice search: Populations. When you want to find the population of a specific city (in this case, Portland), simply ask Google the question and not only will it provide you with an answer to your immediate question, it will show you answers to potential follow up questions.
These answers are for the type of questions people usually ask so in the example given, you"ll also get the population of Seattle and San Francisco on an interactive graph so you can see just how much the population changed over time.
It"s not a major change, but it's a useful one when you're debating with your friends just how many people are currently living in London, or for table quizzes if you"ve no qualms about cheating.