Converting Excel cell to percentage using epplus

The correct formula is as follows:

 foreach (var dc in dateColumns)
  {
    sheet.Cells[2, dc, rowCount + 1, dc].Style.Numberformat.Format ="#0.00%";
  }

The Double slash in "#0\\.00%" leads to very unusual numbers when you try to expand the decimal places later

I found it!

I tried

 foreach (var dc in dateColumns)
  {
    sheet.Cells[2, dc, rowCount + 1, dc].Style.Numberformat.Format ="#0\\.00%";
   }