RE: How many go unseen ?
That's a tough question, if we were going with just dear that are over 3.5 years old for just one year of their life (say a 4.5 year old during the year that he is that age) I'd say maybe as high as 20+% go unseen....now, say what are the chances of that 4.5 year old has never been seen, then i'd say it drops to probably less than 5%