I was looking at the name cloud above and got a bit fed up with the big missing surname entry. This looks like sloppy work on my part.
I checked in Gramps and 4% of my database was missing surnames, this is not good. There will always be a few names that are unknown and I could cheat by adding the married name to British women, most names that are missing are from married women whose birth name is unknown and that is a peculiarity of Britain and the colonies, the rest of the world value women higher and they use their birth name all their life. Using a married name though does introduce a chance for errors, there are some cases where cousins with the same name married and they may get overlooked with using married names as birth names.
Some of these missing names will be for ever clouded in mystery, like Agnes, the wife of John Grist. She is only mentioned on her burial record and the baptism of her children. She may have married before the reformation or before the new church of England started keeping records, or they may have been a record that has got lost in the last 500 years. I doubt I will ever find her name or the parents of either of them, common peasants were not worth recording.
With a lot of new parish records coming online over the last few months and the GRO search site now having mothers maiden names back to 1837 there were lots of places where I could fill in names, and in many cases get research back one or two generations. It took some time but missing names are now less than 1% of the total 8000 people in the tree.
It is always useful to go back over old research, new facts pop up all the time and allow a better picture of our ancestors lives.