Search stats - Browser vs. Search engine

Looking for usage stats on browser-based search, and other methods

[xbase234]

I'm looking for information/stats on the browser-search landscape. I'm particularly interested in knowing the following:

1) The percent of searches initiated from a search box directly in the browser (i.e. Firefox or Opera dropdown search boxes, not toolbars)

2) The percent of searches initiated from a toolbar search app like the Google toolbar or similar

3) The percent of searches initiated directly from a website (ex. search from the Yahoo homepage).

4) The percent initiated from the address bar, not including domains

If you know of a link to reports, or can offer advice in this area, it is much appreciated.

Thanks in advance