I'd like to see a simple line graph of a keyword and my position in the SERPs for that keyword plotted over a time. For instance, I'd like see my position for

I'd like to see a simple line graph of a keyword and my position in the SERPs for that keyword plotted over a time. For instance, I'd like see my position for the keyword "folsom county apple juice" at a certain point in Jan, Feb, Mar, Apr... etc.. Options for weekly, monthly, yearly. I was at an SEO talk once and asked about that, and I got some canned response like "search optimization isn't a 'keyword' focused business anymore". Maybe that's true, but I can see the ranks in Google Webmaster tools, and that's what I'd like to see plotted. I don't even care if it's an approximation, what I'm mostly interested in is the trend line. Am I moving up or moving down over time? Granted, I'm pretty lazy and this might exist, but I've looked at a few services and I haven't seen it yet.