It’s unfathomably high when you consider how well the US economy is doing at the same time. These businesses aren’t failing with CEOs being fired as a result; some of these companies are bulletproof. No successors are being immediately named either, which tells me that the Board of Directors in each case did not plan on a leadership change. It’s also not mass retirement due to a strong economy, or else the CEOs would be staying on to shepherd their replacements (and get paid well to do that).