Well, first, I bled on an off during the first trimester of this pg, and am now almost 29 weeks with healthy twins. I had a subchorionic hematoma (small blood clot in my uterus) at 8 weeks, followed by partial placenta previa at 10-15 weeks. Both resolved on their own without any complications or intervention.
Second, like any statistic, I think this one needs to be taken with a grain of salt. There is nothing in this that separates out the reasons for the bleeding (subchorionic hematoma, placenta previa, cervical irritation, to name a few) and ties those specific reasons to the chances of miscarriage. Similarly, the statistic itself does not separate for risk factors in pregnancy. Basically, the statistic simply considers all women who have bled for any reason during any point in pregnancy, and takes the number of those who have miscarried to render its final number.
I think if you really want to know your risk of miscarrying due to bleeding, you need to look at the specific reason for the bleeding, if there is one, and the risk of miscarrying due to that specific reason.