Should blanks all be in same row?

My schema has several fields set to 1% blanks, intending to test how an app deals with records that have one or another field blank. I generated 1000 rows and all the blanks occurred in the same records. That is, all the blanks for field 1 occurred in the same records as all the blanks for field 2 as all the blanks for field 3, etc. See screenshots of schema for reference.

Is there a way to avoid this?

Schema

And, here’s a screenshot of the preview for reference.
image