1. Math in the News
Issue 81
The Growth of America
In this issue we look at census and demographic data for the U.S.

2. Throughout most of its history America has grown in size
and population. Let’s first look at how America expanded in
terms of the number of states added to the Union.

3. This table shows how
America grew through
the increase in the
number of states.
(The first 13 states
are lumped into 1787,
when the Constitution
was ratified.)

4. Here is the graph of the data in the table. This shows that states
were added to the country in a steady, consistent manner.

5. This graph takes the same data and displays it cumulatively.

6. This graph is a scatterplot of the data. As you can see it is a linear
function.

7. This table shows how
America’s population
has grown from 1790
to the start of this
decade. (Source:
Census Bureau.)

8. Here is a graph of the data. As you can see the population has
grown in a non-linear manner.

9. Here is a scatterplot of the same data.

10. Up until the 1960s, there were three forces at work to grow
the US population: (1) new states, (2) normal population
growth, and (3) immigration. But since the 1960s no new
states have been added.

11. Since the 1980’s the normal growth of the US population
has been flat to a slight decline. This table shows the net
change based on new births vs. deaths.

12. One of the biggest drivers of the US population now and
for the foreseeable future is immigration. This chart from
the Census Bureau shows how immigration is set to
overtake the normal growth in population.

13. The New Frontier in better understanding America’s
growth isn’t Geographic, but Demographic.