Excess rows in Xcel 2013

I have created a table with content( drop down list) in most columns. I have generated just over 1,000,000 rows. How can I delete the unused rows?

CI

Tried several variations on manually selecting the unneeded rows non-of which worked. One response indictaed there was too much content to delete. and I crashed the table once trying this. I also tried selecting just a few rows and nothing happened. Slecting a few rows at a time will not be practical since there are over 1 m rows

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