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Double-checking NPR's income data

According to NPR.org, "After 1980, only the top 1% saw their incomes rise." Flowing Data quoted this figure:

You can see the trend more clearly here (note that the y-axis shows growth in year X vs. 1917; so, it's clear that income growth stagnated for the bottom 90% in the last 40 years):

Their data came from World Top Incomes Database.

I decided to double-check this claim using a dataset from census.gov

Python code:

%matplotlib inline
import pandas as pd
import seaborn as sns
sns.set(context="poster", style="dark")
import mpld3

# csv location = https://github.com/aflyax/Python/blob/master/income/income_2013_dollars.csv
income_df = pd.read_csv("income_2013_dollars.csv", sep='\t', thousands=',')
income_df.columns = ["year", "lowest fifth", "second fifth", "third fifth", "fourth fifth", "top fifth", "top 5%"]
income_df.sort(columns="year", inplace=True)
income_df.head()
year lowest fifth second fifth third fifth fourth fifth top fifth top 5%
47 1966 14747 32739 46844 62710 107026 164340
46 1967 14977 33490 48138 64560 113997 180362
45 1968 16143 35208 50300 67270 114947 177194
44 1969 16656 36783 52635 70510 120757 185476
43 1970 16404 36271 52445 70744 121652 185243
income_df.tail()
year lowest fifth second fifth third fifth fourth fifth top fifth top 5%
4 2009 16604 40232 65061 98788 205788 352985
3 2010 15944 39436 64276 98064 199918 334275
2 2011 15828 38898 63212 96563 205003 356839
1 2012 15760 38739 63372 96861 205503 357458
0 2013 16109 39514 63916 97207 206687 358722
ax = income_df.plot(x="year")
ax.set_ylabel("income")
ax.set_xlabel("year")
print("feel free to interact with the graph:")
mpld3.display() # to make interactive graph

income_df[income_df.year.isin([1970, 2000, 2013])]
year lowest fifth second fifth third fifth fourth fifth top fifth top 5%
1970 16404 36271 52445 70744 121652 185243
2000 19103 43678 68646 101170 212266 376138
2013 16109 39514 63916 97207 206687 358722

Conclusion: While it is true that the lowest fifth stagnated since 1970, the second, the third, and the fourth fifths (and, of course, the top fifth) increased their income. (Although all groups, including the top 5%, seem to have stagnated since 2000.)

This is a slightly different story from "after 1980, only the top 1% saw their incomes rise". (It is also beside the point that neither NPR's nor the above graph show mobility. I.e., the same person in 1970 and today is unlikely to belong to the same "income class". These data also do not include any information on immigration or unemployment.)

Notebook for this code is here.

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