I have an associative array in awk that gets populated like this:

```
chr_count[$3]++

```

When I try to print my `chr_counts`, I use this:

```
for (i in chr_count) {
    print i,":",chr_count[i];
}

```

But not surprisingly, the order of i is not sorted in any way.
Is there an easy way to iterate over the sorted keys of `chr_count`?