Decision Tree Null values


I am trying to see percentage of null values in decision tree algorithm.

I can use replace like 'null' and i can see in string values but integer values seeing missing values or changing integer to string.

I want to see percentage of null values for all columns in decision tree algorithm. It must be like the attachment.

How can i do it? 

I would suggest to replace those missing values indicated by "?" with "null" or "missing" -- they are then treated as real values and visible in the dec tree.

Thank you for your suggestion.

You are right but it will solve for string values.

For integer values, if i replace "?" with "null" all int variables change to string variable.