Determine whether a set of age labels refer to one-year, five-year, or life-table age groups.
Details
The valid types of age labels are:
"single". One-year age groups, eg"0"or"55", and possibly an open age group, eg"90+"."five". Five-year age groups, eg"0-4"or"55-59", and possibly an open age group, eg"100+"."lt". Life table age groups, eg"0","1-4","5-9","55-59", or"80+".
If x does not fit any of these
descriptions, then age_group_type() throws
an error.
If x could belong to
more than one type, then age_group_type()
prefers "single" to "five" and "lt",
and prefers "five" to "lt".
