"Population growth over the last 7 years"

Question

Hey there,

does the sentence "over the last 7 years, the US-population has grown by 7%" mean that the US-population grew by 4% every year over the last 7 years? Otherwise it doesn't make sense in my opinion to calculate the number of 7 years old children by 4.67m * 1.04.

As I understood the sentence, comparing the US-population now and 7 years ago, today there are 4% more people. Therefore, we would calculate the annual growth by 4% / 7 years being 0.57% population growth per year and leading to a number of 7 year old children of 4.67 * 1.0057 = 4.7m.

Would appreciate if you could clear up my confusion!

Cheers

Answer 1

Hi Yannik,

Of course, let me clear up your confusion:

In the additional information of section "1.1.1. Revenues", it is stated "Over the last 7 years, the US population has grown by 4%.” However, there is no mention of annual growth, so this is total percentage growth.
As such, the calculation of all 7-year-old children, i.e., the number of children born 7 years ago, is simply 4.67m ÷ (1 + 4%) ≈ 4.49m.
Regarding your calculations in the second paragraph, please keep in mind that you have to divide by "1+growth rate" to understand past figures, calculate the annual growth rate by taking the 7th root of "1 + 4%" and subtracting 1 (even if not necessary, as shown above), and if you want to take the detour of calculating the annual growth rate first, you have to calculate last year's number of children seven times (even if not necessary, as shown above).

Best,

Hagen