What does "it" mean?

Hi, everyone. I'm ready this and find the last sentence quite vague.

"So, although these drugs don’t have very many therapeutic benefits, they do carry risks to health and side effects. Probably with the SSRIs, the most commonly prescribed type of antidepressant – SSRI stands for selective serotonin reuptake inhibitor – the most commonly experienced side effect is sexual dysfunction, treatment-emergent sexual dysfunction. And that means people who before entering the study did not suffer from sexual dysfunction. After the study, they are suffering from sexual dysfunction after being given treatment.

Now, that happens at a very low rate for people who are given placebos in these studies. For people given SSRIs, the rate of sexual dysfunction, new sexual dysfunction, is between 70 and 80 percent. It’s phenomenal."

What does "it" in the last sentence refer to? The rate of sexual dysfunction or something?
Thanks for your answer!