please help me!

what was the percentage of african slaves in the north, south,east, and west in the years of 1820,1835,1845, and 1860??

You may have to search and research, but once you learn some good sources and methods, you should have success. In addition to searching on the Internet, you also need to make best friends with the reference librarian(s) in your local or college library. Libraries these days subscribe to enormous research databases, and they are often more useful than Internet searches. Ask your librarian if you have access to EBSCOHost -- it has several databases within it, including a huge one for academic research.

For Internet searching:
http://hanlib.sou.edu/searchtools/
At this webpage, you can go immediately to the search sites (first three columns across the top) -- or even better you can scroll down until you see the section called HOW TO SEARCH THE INTERNET. Those are the links to start with. You'll not only learn how to come up with good search terms, but also how to evaluate the webpages you get as results. Some will be good and others will be garbage. You need to know how to tell the difference.

My favorite way to search is to go to Google's advanced search page http://www.google.com/advanced_search?hl=en and put my search words or phrases into the first or second search box (either "all the words" or "exact phrase"). Another is to start out at http://scholar.google.com. However, there many other strategies for searching you can use, and the HOW TO SEARCH THE INTERNET section will help you best.

Learning to use Google or other search engines can save you time and help you learn to find information efficiently. Here are some websites that can teach you how:

http://www.lib.berkeley.edu/TeachingLib/Guides/Internet/FindInfo.html

http://hanlib.sou.edu/searchtools/searchtips.html

http://www.pandia.com/goalgetter/index.html

http://websearch.about.com/mbody.htm?once=true&COB=home&PM=112_100_T

... and one to help you judge whether a particular website's information is worth your time:

http://hanlib.sou.edu/searchtools/evaluate.html