I am new to Weka. I ran a random forest algorithm with wrapper method for attribute selection with 5-fold cross validation. However, I get confused on interpreting the result. Basically, the result is as:

number of folds (%) attribute
4(80%) 1 length
2(60%) 2 word_file
5(100%) 3 contains_pdf
1(20%) 4 name
3(60%) 5 contains_url

and so on.
What are the numbers and what is the best way to select features?

Any help is much appreciated. Thanks in advance.