I too sell much more than that. I don't hold a huge portfolio but most are in a couple of very specific niches that I have first hand experience in. I know exactly who my customer is, how to communicate with them, their mindset and generally what they can pay. Those that don't sell over time, I can develop and monetise myself as i have experience there. I don't make huge money but things keep ticking over. I do sell much less outside these niches but it would still be more than 1 per year or 1 per hundred. I must add that most of my portfolio are cctld domains.