First take a stock of what all you did like some sample questions below.
- Have you delivered specific results? Which ones? Estimate how much they were worth.
- Has your communication improved? How so?
- Are you more efficient than before? How do you know?
- Do you know the business better? How does this translate to the company’s bottom line?
- Have you developed new skills? What kind?
Then brainstorm ways you could add value above and beyond what you’ve already done like below sample questions.
- Maybe there’s a project you could lead?
- Maybe you’ve got an idea for a system that could streamline communication?
- Maybe you’re willing to get additional training and certifications to take on more responsibilities?
- Create a specific plan for how you can solve problems in their company
- Or any other ideas you have that could help your employer or boss out
Don't go with a number. End the meeting then and setup another one after thinking about one of these ideas and showing what you have progressed.
This shows to your boss that you're focused on big stuff and working on it.
The % will take care of itself.
Good luck!