This story is fishy in many ways, not just the lack of an appropriate comparison group.
According to the article, 7% of 950 attempters succeed each month (a far far lower rate of success than is found among males). That makes 2.3 suicides per day. Where does the number “18” come from?
If you take 7.82 and multiply by 2.3, you get 18. That’s where they got 18. They pulled it out of their posterior.