Code:
program:
## You can remove this if you don't want it, just change the next 'elif' to an 'if'
if ($$#percentread >=#1 && $$#percentread <=#99)
then 'Currently Reading'
elif $$#percentread >=#100
then 'Read'
## Change 'Undefined' to '' if you prefer a null value
elif $$#percentread == 'None'
then 'Undefined'
elif $$#percentread >=#0
then 'Unread'
fi