I have a table in Numbers with a row for each person with a header with consecutive days of the year (every day is represented) and starting at the END of each row, I want to find out how many days since the last time the number has changed.

I have a table in Numbers with a row for each person with a header with consecutive days of the year (every day is represented) and starting at the END of each row, I want to find out how many days since the last time the number has changed.

In the example below, starting at the END of the row and looking back, the last time the number changed was 6 days before.

Line 2 - Five days before

Line 3 - Four days before

and so on. How formula do you use to figure out how many days since the last time the number has changed?