Best approach to pull data from email

Question

I am a teacher at a high school that uses an online program to do some homework and quizzes. At present, I get the emails and manually read them and enter the scores by hand into a spreadsheet. I have been doing some searching around for scripts that can automate this for me, but first I think I need advice on the process itself. Here is a sample email to show you what the data looks like:
I am currently using Automator to try to design a workflow whereby I get the selected messages, run an AppleScript that pulls the data out, copy this to clipboard, then paste the clipboard either into a text file or spreadsheet. I found a few scripts out there (like this one) that seem to have some of the pieces I need, but I can't get the scripts to work when I customize them to my purpose. Where I seem to really be getting stuck is the design of the script:
--all I need is the name and the percentage score, or the "you answered x correctly" part
--should I try to set the script to key in on the percent sign itself, since that's a unique character? or is there a better way to aim?
Here's a sample script I'm trying:
on run {input, parameters}
    tell application "Mail"
        set theSelectedMessage to selection
        if (count of theSelectedMessage) is equal to 0 then
            display dialog "Please select a message in Mail first, then run this script again."
        else if (count of theSelectedMessage) is equal to 1 then
            set thisMessage to item 1 of theSelectedMessage
            set theBody to content of thisMessage
            set theTargetText to paragraph 3 of theBody
        else
            display dialog "Please select only one message in Mail first, then run this script again."
            extract name from thisMessage
        end if
    end tell
    return input
end run
Any and all help is greatly appreciated!

Answer 1

Thanks to Hiroto!
pull content from mail message & export to excel