Thanks, wiggy! I did know this stuff since I've been involved in various projects since 2014 in observing orbital debris in high-earth orbit (i.e., geosynchronous orbit) but hadn't seen that web page before. It's very good and summarises things well. It's something I will definitely use in the future if and when I need to explain orbital debris and its potential effects. I think many people concentrate on orbital debris being a problem in low-earth orbit or something that's a threat to astronauts and space stations - which of course it is - but don't consider the threat to our whole satellite communication network.