According to a census bureau, from 2000 to 2016 the population of a certain region grew from 261 million to 293 million. What was the percent of increase? The percent of increase is $\square \%$. (Round to one decimal place as needed.)

Step 1 ：According to a census bureau, from 2000 to 2016 the population of a certain region grew from 261 million to 293 million. We are asked to find the percent of increase.

Step 2 ：To find the percent of increase, we need to subtract the initial population from the final population, divide the result by the initial population, and then multiply by 100 to convert to a percentage.

Step 3 ：Let's denote the initial population as \(P_{i}\) and the final population as \(P_{f}\). In our case, \(P_{i} = 261\) million and \(P_{f} = 293\) million.

Step 4 ：The percent of increase can be calculated using the formula: \[\%\ increase = \frac{{P_{f} - P_{i}}}{{P_{i}}} \times 100\]

Step 5 ：Substituting the given values into the formula, we get: \[\%\ increase = \frac{{293 - 261}}{{261}} \times 100\]

Step 6 ：Solving the above expression, we find that the percent of increase is approximately 12.3\%

Step 7 ：Final Answer: The percent of increase is \(\boxed{12.3\%}\)