sort issue

I am inventorying a coin collection. Coins with mint marks are sorted separately, and I want them listed within the proper sequence.

what I want is this:
1987
1987 d
1988
1988 d
1989
1989 d

what i'm getting is this:
1987
1988
1989
1987 d
1988 d
1989 d

Is there a command or function that will list coins with mint marks in the same sequence as those without mint marks?
Thank you!

Hi,
If you format the column as text then it will sort the values correctly.
It is currently treating the ones without the mint marks as numbers and prioritizing them over the ones with mint marks, which it treats as text. But if you make it all 'text' then it will treat it the same.

Cheers,
Tocs

Thank you for the prompt reply.
Your fix seems so obvious and simple.
I highlighted the column with dates, right clicked, chose format cells, text, ok
saved my work
highlighted the column again, sort a-z, ok
no luck. Still sorted the column incorrectly
not sure what i might be doing wrong
tried three times with same result
what might you suggest?
Thanks

1.Select column.

2.Data -> Text to Columns -> Next ->Next , Choose -> Text -> Finish

3. Sort A to Z.

Awesome!!! It worked!!!
Cant thank you enough.
You saved me hours of work!
Thanks!

You're welcome!

My fix will only work for new entries. I forgot it doesn't change already entered cells.
But as you have already found out what Phuocam wrote will change the cells already entered.