I ball parked the number of tries this last year, from mid summer'09 --> the end of spring'10 semester, to somewhere between 700 and 900. (depending on how you count those sketchbook pages full of thumbnails)
And if I also include the last 3 years efforts I'd say modestly I'm around 2500 tries total, cause the first few years didn't demand the same volume of work. So if I can pick up the pace and try to get in around a 1000 a year I'll be at 10,000 by 2017. Which is also when I'll be re-naming this blog "Do or Do not..."