Here’s a really good report which you can set up in Google Analytics (or most website traffic analysis applications) to give you a really interesting trend. It allows you to get an overall graph of the amount of people finding your website from the search engines using terms not related to your company name …in other words, the generic product related searches which are the most important in attracting people who are new to your company.
It’s quite simple: set up a ‘segment’ showing the traffic which comes from Google organic (natural) search and which does not include your company name. This is much better at representing your core strength in the search engines than just Google traffic in general, as a large part of that traffic will be people simply looking up your company website. As it’s a segment, rather than a filter, you can backdate the data to see how you’ve been doing in Google ever since you first got analytics installed on your site.
There’s a full writeup in How to Use Advanced Segments in Google Analytics to Isolate SEO Problems on Search Engine Journal.