Cleans the data on the motivation to quit smoking and the use of support.
smk_quit(data)
Data table - the Health Survey for England data.
Returns an updated data table with:
giveup_smk - whether a current smoker wants to quit smoking (yes, no).
Only tested on England data Use of support not currently incorporated
if (FALSE) {
data <- read_2001()
data <- smk_quit(data)
}