I dare to say that the numbers on Roland Vink's site represent less than 50% of the actually shipped units
For pre-AI, AI and AI-S lenses, I have serial numbers within 100s or 10s of the known starting point. These are the lenses I have the best information on, because I like them the most and spent more time (25+ years) researching them, and there is a base of collectors and enthusiasts who are willing to share new information with me. In theory I have the same chance of of finding serials just as close to the last lens made as the first, so for most if not all lenses, my numbers should be close to 100% of the units shipped.
For older AF lenses, photographers tend to send me early serial numbers when a new lens comes to market. After that interest tends to drop off so I get less frequent updates. Like the manual lenses, I also spent a lot of time collecting more serial numbers from pictures on auction sites. Most of these lenses don't interest me quite as much, so my numbers may not be as complete, maybe within 1000s of the starting and end points. I'd still say my numbers are well above 90% of units shipped.
The high volume kit zooms are hardest to keep track of, they are churned out so fast it is hard to keep up with production numbers. Plus they are of less interest to me and others in general so I am less inclined to spend time trying to find new serial numbers. So where production of some lenses may be in the millions, my numbers could be hundreds of thousands short, but I would say in most cases my numbers are still well above 50% and probably much higher.
For recent lenses that are in current production, the numbers on my site can be quite mixed. A photographer may send me the serial number of their shiny new lens, so for the moment my numbers are probably close to 100%. But then I may not get another update for a year or two while production keeps going so the numbers for that lens get progressively more out of date. But even here I'd say my figures are still pretty good. On my site I flag lenses which are new within the last 6 months so you have some indication of how up to date the serial numbers are.
For cameras, my numbers are less accurate. Some of the older professional cameras are well covered, the cheaper high-volume cameras are less so for the same reasons as the high-volume lenses. Also, Nikon have a bad practice of splitting up the serial numbers into multiple regional zones, which makes it much harder to keep track serial numbers in each zone. For some camera models it is possible that I have missed some smaller regions completely. I can only work with the information that I am given (I don't have any inside knowledge from Nikon) but the aim of that page is more to give an overview of specifications and an indication of the regional serial numbers, not the complete picture.