How do I determine the percentile value of a series using formula language?

You can use one of the following functions.

Percentile(series, percentile)

Percentile(series, percentile, window)

In the first function, the percentile is calculated over the entire time series, yielding one value.

The second function will calculate the percentile on a rolling window, set by the second variable.

Examples:

Percentile(sek, 70)

Percentile(sek, 70, YearLength())