What percentage of cases does dizziness indicate brain tumor? i read that actually brain tumor is rare with dizziness

Tumors & dizziness: Very rare, mostly metastatic tumors in brain from other organs.

Indeed rare: Tumors of the auditory nerve may present with dizzy spells and hearing loss. Tumors of the cerebellum or brainstem may start with nausea and dizziness and then vomiting. Tumors will result in slowly progressive symptoms. Episodes of dizziness that last short intervals are not due to tumors. Inner ear pressure and/or inflammation can produce these symptoms as can migraine.

Correct: What you have read is correct: dizziness is rarely a symptom of a brain tumor, and is far more likely to be due to a disorder of the inner or middle ear. The actual percentage of patients with dizziness who turn out to have a brain tumor is small, but I have not seen a published study with an exact number.