Birth counts

Description

An updated version of the historical Arbuthnot dataset. Numbers of boys and girls born in the United States between 1940 and 2002.

Usage

present

Format

A data frame with 63 observations on the following 3 variables.

year

Year.

boys

Number of boys born.

girls

Number of girls born.

Source

Mathews, T. J., and Brady E. Hamilton. "Trend analysis of the sex ratio at birth in the United States." National vital statistics reports 53.20 (2005): 1-17.

Examples

library(ggplot2)

ggplot(present, mapping = aes(x = year, y = boys / girls)) +
  geom_line()