Type of problem: Percentage decrease
Step 1: Find the difference between the two numbers
(Difference = original number - new number)
164,000,000 - 155,000,000 = 9,000,000
Step 2: Divide the difference by the original number
9,000,000 / 164,000,000 = 0.05487804878
Step 3: Multiply by 100 and round to find the percent
0.05487804878 x 100 = 5.48780487805
Round to one place = 5.5
Answer: 5.5% decrease in the population
Hope this helps!! :)