my annual goal is both books and pages. so i count the short story collection as read, even if i did not read all of the stories, but i mark the page amount as a % of the stories read. so if i read 12 of 20 stories and the whole book is 700 pages. i 700/20*12 and list that number.

counting pages keeps me from choosing short books just to meet the goal.

but ultimately it is up to you and what you feel comfortable doing.