Based on the information provided, I was unable to find specific data on the frequency of dizziness experienced by individuals taking Lipitor (atorvastatin). However, dizziness is a commonly reported side effect associated with many statin medications, which include Lipitor.

According to the Lipitor Prescribing Information, the most common side effects reported by patients treated with Lipitor (and at a rate at least twice that of placebo) are:

- Nasopharyngitis (inflammation of the throat and nasal passages)
- Arthralgia (joint pain)
- Diarrhea
- Pain in extremity (pain in arms or legs)
- Urticaria (hives)

Dizziness is listed as a less common side effect, occurring in 2-5% of patients taking Lipitor.

It is important to note that everyone's reaction to medication is different, and some people may experience side effects more or less frequently than others. If you are taking Lipitor and are experiencing dizziness or any other side effects, it is recommended that you consult your healthcare provider.

Sources:

1. [Lipitor Prescribing Information](https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/020582s065,020780s040,021086s031,021103s032,021186s029lbl.pdf)
2. [DrugPatentWatch.com - Lipitor](https://www.drugpatentwatch.com/drugs/lipitor)