On 77 small sites we could crawl completely, 87.0% had at least one sitemap URL that no internal link reaches, and 8.5% of their 16,587 sitemap URLs were orphaned.
Source: PageSpeed Matters. Crawl and sitemap check of 77 small sites, Oct 2026.
Small sites only; links that appear only after JavaScript interaction can make a page look orphaned.
Source: Orphan Pages: 87% of Small Sites Have Sitemap URLs Nothing Links To - PageSpeed Matters