Need function to find when number in row doubles

I have a row of numbers that steadily increases I am interested having a formula or function to tell me how many days it has taken for the number to double.

Day 1 2 3 4 5 6 7 8 9 10 11 12 13
Data 100 111 125 138 163 175 189 200 225 255 275 325 400

Function 7 7 7 7 6 5


I tried a formula with the IFS statement but it gives me the #NAME? error

=IFS(BT6/BS6>2,"1",BT6/BR6>2,"2",BT6/BQ6>2,"3",BT6/BP6>2,"4",BT6/BO6>2,"5",BT6/BN6>2,"6",BT6/BM6>2,"7",BT6/BL6>2,"8",BT6/BK6>2,"9",BT6/BJ6>2,"10"BT6/BI6>2,"11",BT6/BH6>2,"12")

Attached a spreadsheet example

Hi JackBox,

You may want to follow the guidance in the "yellow" banner above and post a sample workbook with a clear picture of before and after.