Answer:
Between 2000 and 2010, Nevada went from having 1,998,257 inhabitants to 2,700,551, thus gaining 702,294 inhabitants.
In the same period, California passed from 33,871,648 people to 37,253,956 people; therefore, it gained 3,382,308 settlers.
Montana, in turn, had a small gain in that period: it went from 902,195 to 969,415 inhabitants, a gain of only 67,220.
Finally, Wyoming gained 69,844 people from 2000 to 2010: it passed from 493,782 to 563,626 people.
As we can see, California had the largest gain in population between 2000 and 2010, as it gained 3,382,308 inhabitants.
