How to update the range in a formula automatically when adding rows of data to a worksheet

Hello!

Can anyone advise on how I might be able to get the formulas that I am using on a worksheet to automatically update to include all cells in the column that contain data when adding new lines (rows) to the worksheet?

For example:

In cell C2-I have the formula "=COUNTIF(E8:E17,"ONTIME") and the range is specified as E8:E17 because there is no additional information beyond row #17. However--I routinely add rows to this worksheet and would like the range in the formula to automatically update from E8:E17 to E8:E??? --whatever row is that last row that contains information. Currently--I go into every formula on the worksheet and manually update the range which is time consuming and includes a high risk of making an entry error--is there a way to "tell" Excel to automatically update that range in all formulas to extend to the last row on the sheet that contains data/information?

I look forward to any insight anyone might be able to offer...

Thank You!
Angela