Although not a member of the EU, Norway participates in the European-wide regulatory framework for granting marketing authorization to pharmaceutical products. Maximum prices for prescription medicines are determined by the Norwegian Medicines Agency that sets pharmacy purchase prices (based on prices in other Northern European countries) and the Ministry of Health that sets pharmacy margins. A "discount sharing model" encourages pharmacies to perform parallel import and generic switching by allowing them to keep up to 50% of the difference between maximum price and actual price. The costs of pharmaceuticals in Norway are covered in part by the public budget and in part directly by the patient. Over one-half of pharmaceutical costs are borne by the Norwegian National Insurance Administration through the reimbursement scheme; membership in this program is mandatory, and costs are covered through taxes from employers and employees. Over 90% of reimbursed drug sales are accounted for by the established product list for general reimbursement, but supplementary reimbursement can be granted on the basis of individual patient applications and also to ensure that all patients with serious communicable diseases are given adequate treatment without costs to the patient (e.g., HIV/AIDS, tuberculosis). Patient copayment currently amounts to 36% of the total amount of prescriptions; the maximum per prescription is 48 euros, and total within a single calendar year is 180 euros. Copayments for physician visits, radiology examinations, and laboratory tests, can be included in this amount. The overall system is now undergoing reevaluation, as it has been criticized for being complicated and difficult to comprehend for the users.