Data sorting problem

Hello.
I have a table with monthly historic exchange rates that I need to transform into a table with daily historic exchange rates.
The table looks like this:

1950:01 7.15
1950:02 7.16
1950:03 7.17
1950:04 7.18
1950:05 7.19
1950:06 7.20
1950:07 7.21
1950:08 7.22
1950:09 7.23
1950:10 7.24
1950:11 7.25
1950:12 7.26
1951:01 7.27
1951:02 7.28
1951:03 7.29
1951:04 7.30
1951:05 7.31
1951:06 7.32
1951:07 7.33
1951:08 7.34
1951:09 7.35
1951:10 7.36
1951:11 7.37
1951:12 7.38

I'm very inexperienced with excel and I couldn't find a way to do it with vlookup, so I would appreciate it if you could give me a tip as to how such a thing might be accomplished. I attached a sample.

Thanks for the help