How common is a missed miscarriage in second trimester?

I’m 17 weeks and my anxiety about losing the baby is so bad. I previously had a missed miscarriage last spring when I was 10 weeks pregnant with twins and that ultrasound visit still haunts me. I was having zero miscarriage symptoms so I had no idea. I’m having a hard time being excited because I’m so nervous that it’s going to happen again without any obvious symptoms. I’ve looked at the data analyzer and I know my miscarriage rate has gone down, but having a hard time finding info about how common missed miscarriages are this far along.