Here is a bash script that extracts the decimal number that immediately follows the "@" symbol in each line of the data and formats it as a vertical column:
```bash
#!/bin/bash

# Extract the decimal number that immediately follows the "@" symbol in each line of the data
grep -oE "@[0-9]+\.[0-9]+" data.txt | cut -c2- > column.txt

# Format the extracted numbers as a vertical column
cat column.txt | column
```

The result:
```
2.30
4.35
1.13
4.10
4.35
2.60
1.21
3.90
```
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