You know, I've seen all kinds of data that says ranking #1 means you get 33% of the clicks, or up to 80%. (I take it all with a grain of salt.) Matter is: if (this is according to my AdWords; I just looked) "business hosted VOIP" gets 58 clicks per month (yes, I swear that is the number they gave me when I selected "exact" and "local monthly" but I also really like to look at what the smallest opportunity would be), then 1/3 of 58 isn't many. Even 80% of that isn't many and matches back to the numbers you are talking about.
(590 comes up for "broad" in AdWords which isn't anything I use, mostly, again, because I like to look at what the smallest size could be so I know what I could be getting myself into.)
As for lower ranking pages having more traffic, that can vary as well. You'll hear people say searchers go for the top 5, but if a page ranks #6 for a word that has 11,500 searches a month, there's more opportunity for traffic than a #1 ranking for a KW that gets 58, you know?
Ideally, a bounce rate of 30% is where you want to be - you aren't that far off from there, but if 50% is the average, I'd look into additional keyword opportunities. For as much stats and science is behind SEO, there's just as much art to it 