How can I delete rows with periodically in an excel file with matlab?

Hi Everyone,

I collected some data from a test system. But these datas are very huge rows(~8 billions rows) beacuse of high frequency. And i want to reduce this number of data. Do you know how can i delete number of rows in excel file with periodically? I thought i can delete one row spacing like that:

row1: hold

row2:remove

row3:hold

row4:remove

......

but i am so new in matlab and i dont know necessary codes and how i can write them. if you can help me i really be grateful.