USA Births Data¶

By Jake VanderPlas. See http://github.com/jakevdp/data-CDCbirths/

This dataset records birth rates in the USA by year. It was compiled from data on the CDC website and is aggregated so as to comply with their terms of use.

(This was inspired by Andrew Gelman's recent NYC R Meetup talk. Some of his writeup on the topic can be seen on his blog)

In [1]:

%matplotlib inline
import matplotlib as mpl
import matplotlib.pyplot as plt
import seaborn; seaborn.set()

import pandas as pd
import numpy as np

In [2]:

births = pd.read_csv('births.csv')
births.head()

Out[2]:

	year	month	day	gender	births
0	1969	1	1	F	4046
1	1969	1	1	M	4440
2	1969	1	2	F	4454
3	1969	1	2	M	4548
4	1969	1	3	F	4548

In [3]:

# Some data is mis-reported; e.g. June 31st, etc.
# remove these outliers via robust sigma-clipping
quartiles = np.percentile(births['births'], [25, 50, 75])
mu = quartiles[1]
sig = 0.7413 * (quartiles[2] - quartiles[0])
births = births.query('(births > @mu - 5 * @sig) & (births < @mu + 5 * @sig)')

# set 'day' column to integer; it originally was a string due to nulls
births['day'] = births['day'].astype(int)

In [4]:

# Choose a leap year to display births by date
dates = [pd.datetime(2012, month, day)
         for (month, day) in zip(births['month'], births['day'])]

In [5]:

# Plot the results
fig, ax = plt.subplots(figsize=(8, 6))
births.groupby(dates)['births'].mean().plot(ax=ax)

# Label the plot
ax.text('2012-1-1', 3950, "New Year's Day")
ax.text('2012-7-4', 4250, "Independence Day", ha='center')
ax.text('2012-9-4', 4850, "Labor Day", ha='center')
ax.text('2012-10-31', 4600, "Halloween", ha='right')
ax.text('2012-11-25', 4450, "Thanksgiving", ha='center')
ax.text('2012-12-25', 3800, "Christmas", ha='right')
ax.set(title='USA births by day of year (1969-1988)',
       ylabel='average daily births',
       xlim=('2011-12-20','2013-1-10'),
       ylim=(3700, 5400));

# Format the x axis with centered month labels
ax.xaxis.set_major_locator(mpl.dates.MonthLocator())
ax.xaxis.set_minor_locator(mpl.dates.MonthLocator(bymonthday=15))
ax.xaxis.set_major_formatter(plt.NullFormatter())
ax.xaxis.set_minor_formatter(mpl.dates.DateFormatter('%h'));

Apparently American women really love their holidays!