Epi (version 2.59)

B.dk: Births in Denmark by year and month of birth and sex

Description

The number of live births as entered from printed publications from Statistics Denmark.

Usage

data(B.dk)

Format

A data frame with 1248 observations on the following 4 variables.

year

Year of birth

month

Month of birth

m

Number of male live births

f

Number of female live births

Details

Division of births by month and sex is only available for the years 1957--69 and 2002ff. For the remaining period, the total no. births in each month is divided between the sexes so that the fraction of boys is equal to the overall fraction for the years where the sex information is available.

There is a break in the series at 1920, when Sonderjylland was joined to Denmark.

Examples

data(B.dk)
str(B.dk)
attach(B.dk)
# Plot the no of births and the M/F-ratio
par(las = 1, mar = c(4,4,2,4))
matplot(year + (month - 0.5) / 12, cbind(m, f),
        bty = "n", col = c("blue", "red"), lty = 1, lwd = 1, type = "l",
        ylim = c(0, 5000), xlab = "Date of birth", ylab = "" )
usr <- par()$usr
mtext("Monthly no. births in Denmark", side = 3,
      at = usr[1],  adj = 0.25, line = 1/1.6)
text(usr[1:2] %*% cbind(c(19,1), c(19,1)) / 20,
     usr[3:4] %*% cbind(c(1,19), c(2,18)) / 20,
     c("Boys","Girls"), col = c("blue","red"), adj = 0 ) 
lines(year + (month - 0.5) / 12, (m / (m + f) - 0.5) * 30000, lwd = 1)
axis(side = 4, at = (seq(0.505, 0.525, 0.005)-0.5) * 30000, labels = NA, tcl = -0.3 )
axis(side = 4, at = (50:53 / 100 - 0.5) * 30000, labels = 50:53, tcl = -0.5 )
axis(side = 4, at = (0.54 - 0.5) * 30000, labels = "% boys",
     tick = FALSE, mgp = c(3,0.1,0))
abline(v = 1920, col = gray(0.8))