How much can a landlord for a business with a long term lease raise rent per year?

There is no limit on rent increases on commercial (business) tenants other than as provided in the lease itself--that is, the law does not impose any general limits on this. So if the lease sets out the rent or permitted increases, the landlord would be restricted to that; but if not restricted from increasing by the lease, the landlord is free to set any level of rent the landlord wants.