I am attempting to use the `monthly()` function in Stata to convert a set of month-year pairs from string to numeric. The data for this variable appear as follows:

```
rcsbirth
072005
101993
012001
121994

```

I have been able to do this using the `date()` function:

```
generate childbirth = date(rcsbirth,"MY")

```

Next, I use:

```
format childbirth %td

```

Variable `childbirth` now lists as follows for the respective `rcsbirth` dates:

```
 01jul2005
 01oct1993
 01jan2001
 01dec1994 

```

When I try to apply this very same process using the `monthly()` function, and formatting using `%tm` instead of `date()` with `%td`, it produces all missing values in the new `childbirth` variable. 

Again, I am trying to apply:

```
generate childbirth = monthly(rcsbirth, "MY")

```