Pivoting table for Data Quality

Dear guru of PowerBI,

I've a table with 25 column called Server which has 47k rows.

I've been asked to calculate the data quality for each columns that is to calculate how many blanks in total there are and divided by column.

This was my solution : 
1) Duplicate Server Table in Power Query

2) Pivot all columns to have only 3 columns : server_id , Attribute , Value
    Attribute has the name of the column,
    Value has the content of the column.

But, my Pivot table is big 29 milions rows, that seems wrong to me and powerbi returns "Too much memory, cannot visualize"
How can I achieve that and fix this problem?

Thank you,