For the April vulnerability scorecard, we’re back to having four charts again, 2 each for server and workstation products. Each of the Linux distributions analyzed do not include the full set of product components, as I went through a process to filter out optional and non-comparable components. Mac OS X, on the other hand, had the worst 3-month count for both total and High Severity vulnerabilities. The year-to-date chart shows how the cumulative effect of vulnerabilities differs.”]
Source: https://www.csoonline.com/article/2136933/april-2007—operating-system-vulnerability-scorecard.html