The provided text does not state a specific dollar amount or average cost for workers compensation insurance premiums in California. Instead, it explains that insurance rates are influenced by official industry benchmarks and regulatory guidance.

Key details regarding rates mentioned in the content include:

1. Advisory Pure Premium Rates: The Workers Compensation Insurance Rating Bureau of California (WCIRB) provides industry benchmarks that serve as advisory pure premium rates.
2. Insurer Evaluation: Insurance companies evaluate claims and set rates based on these state guidelines and DIR (Department of Industrial Relations) procedures.
3. Impact on Benefits: Misunderstandings regarding these industry rates can lead to complications in employer-insurer interactions and may ultimately impact claimant benefits.

Because insurance costs vary based on factors like occupation and age-adjusted impairment ratings for disability benefits, the text recommends consulting the California Department of Industrial Relations or a legal professional for specific case evaluations.