Google has critically expanded notice and takedown in another important way: We accept notices for URLs that are not even in our index in the first place. That way, we can collect information even about pages and domains we have not yet crawled. We process these URLs as we do the others. Once one of these not-in-index URLs is approved for takedown, we prophylactically block it from appearing in our Search results, and we take all the additional deterrent measures listed above. We recently discovered that some bulk submitters make very heavy use of this feature. In one sample we found that around 82 percent of the URLs we approved were not in our index (and have therefore never appeared in any search results). How this discovery will influence the further evolution of our processes, only time will tell. It does suggest that the number of takedown notices we get is not a good proxy for the number of allegedly infringing links we serve.
Caleb Donaldson, Beyond the DMCA: How Google Leverages Notice and Takedown at Scale, Landslide (Nov. 2017).