Though I am not sure but Google's share is definately more than 50%(had read somewhere) It is I think 55%
Here is a graphical representation from the Nielsen NetRatings http://searchenginewatch.com/reports/article.php/2156451
I respect your choice to use these search engines, but have a look at CantUfind.com I am 100% biased, but the results speak for themselves. Lets stop making the so called 'big Boys' just that as they will only dictate what we search for, ignore how, where, and how our results are so good, the hard fact is....'They are'. We've worked our nuts off refining the results so that after they get cached on our servers the turnover is even quicker that the others. Please, just try us!