There are multiple problems here. First, steam is BUSY, a whole world of people are trying to download at once. Steam just svcks during major launches.
I downloaded from disk two hours ago. Since then steam has been updating. It started at 96%. It only just hit 97% and that was due to the following fix. I searched the steam support for possible issues for slow downloads. Steam does an autodetect for the local server. It GOT IT WRONG and it was trying to download from a server in another state. I was getting download speeds of about 3 kb/s. varying between zero and twelve. It was saying like 8 days to download originally. Now I am getting up to 175 kb/s. Its moved two percent in the last few minutes. It should be done soon.
So while steam is slow, it is far more probable that its a setting problem. I had to reboot steam after setting it to download from a different server. There may be other things I did not find that will help as once I had this fix I stopped searching. Go to steam, run a search on support for Skyrim and slow, and start trouble shooting. It will be faster than waiting for a reply on a forum or the week or more to download.