How to make a data set rectangular?

[Darkblood]

So I have a data set, the only problem is the years are not continuous (i.e. it jumps from 1920 to 1925 etc etc). I have at least a few thousands gaps to fill so was hoping there would be an easier way to add the rows and fill in the appropriate dates. I put in a formula that tells me how many rows need to be added in each current line (so for the above example it would read 5, so I need to add 4 rows and the numbers 1921-1924 in those rows). Any advice?

 

[Dryver14]

This macro runs down column 1 from row 1 and inserts missing numbers

try on a copy:

Sub KevinFillrows()
Dim i As Long
Dim lastrow As Long
lastrow = Cells(Rows.Count, 1).End(xlUp).Row
    For i = 1 To lastrow
        If Cells(i + 1, 1).Value - Cells(i, 1).Value > 1 Then
            i = i + 1
            Cells(i, 1).EntireRow.Insert
            Cells(i, 1).Value = Cells(i - 1, 1).Value + 1
            i = i - 1
        End If
    Next i
    
End Sub