title: Get a date from ISO week and year in power query
body: <p>I have a column with a year and a ISO week. I would like to get the corresponding date, but at the moment my formula is wrong.</p>
  <p>I have the following table:</p>
  <pre><code>Year  Week 
  2020   52
  2020   53
  2021    1
  2021    2
  </code></pre>
  <p>I used in power query editor the following formula:</p>
  <pre><code>Date.StartOfWeek(Date.AddWeeks(#date([Year], 1, 1), [Week]), Day.Monday)
  </code></pre>
  <p>and I obtained:</p>
  <pre><code>Year  Week  Date
  2020   52   28.12.2020
  2020   53   04.01.2021
  2021    1   04.01.2021
  2021    2   11.01.2021
  </code></pre>
  <p>What I would like to have instead:</p>
  <pre><code>Year  Week  Date
  2020   52   21.12.2020
  2020   53   28.12.2020
  2020    1   04.01.2021
  2021    2   11.01.2021
  </code></pre>
  <p>For example, in DAX, this works:</p>
  <pre><code>Date = DATE([Year],1,-2)-WEEKDAY(DATE([Year],1,3))+[Week]*7
  </code></pre>
  <p>But I would prefer to have it in power query because my data source needs to be updated regularly. Thank you for your attention!</p>