Can I make up numbers if I cannot find real ones?

No. Invented numbers are dishonest and risky. Interviewers often ask how you achieved or measured a result, and references or background checks can expose figures that do not add up.

What can go wrong:

• You cannot explain the number when asked, which damages trust in the whole resume.
• A former manager gives a reference that contradicts your claim.
• An employer may withdraw an offer or dismiss you later if they find false claims.

Honest alternatives:

• Estimate from your real workload, with "about" or "around".
• Use scale or frequency instead of results: team size, number of clients, how often you did a task.
• Describe the change in words: "faster", "fewer errors", "adopted by the whole department".
• Mention recognition: an award, a promotion, positive feedback.

A resume with fewer numbers that are all true is far stronger than one full of figures you cannot stand behind.