Honestly I wish I could tell someone not to worry about the high proportion of unanswered questions with SharePoint as a few things are working against a high answer rate:
1) Comparatively speaking to many other sites, SharePoint is a new product at 10 years old. For example Programming has been around a long while so StackOverflow.com gets plenty of answers. Networking has been around awhile so ServerFault.com gets plenty of answers, etc...
2) SharePoint has a wide breadth, it's nearly impossible to know everything about SharePoint. Hence knowledge is more spread out amongst what people have worked with.
3) SharePoint audience is still somewhat limited compared to the audience for the other sites. Meaning there are fewer people to answer.
So please, don't judge this site by answer %, we probably will never rank compared to the other sites in the StackExchange community.