Creates an age grid according to a specified format.
ageGrid(grid = "compact")A character string specifying one of the following:
"compact", "classic", "extensive", "0-104w",
"0-24m", "0-21y", "0-21yd" or "0-21yc". The
default is "compact", which produces an age grid between 0 and 21
years with 95 points.
A list with five components: format, year,
month, week and day containing the age grid in different
units.
age <- ageGrid("classic")$year