Add Rows

I have a several rows (more than 100 rows) of data.
Can i add a a new row to every alternative row. I am trying not to right click each row manually and insert row.

Any faster way of doing this?

Thanks

Give every row a number 1 to 100
give row 101 to 200 also the numbers 1 to 100

Sort this column and you are ready.

Smart solution.
Simple, but effective.