You are keen to obtain a helicopter pilot's license. A club offers you lessons over two years, with a choice between the following payment terms: 

1. You can either pay the full fees (€10,000) immediately with a 5% discount, or 

2. you can make two equal annual payments, the first one due immediately, and the second one due after one year. 

At what interest rate would these two options work out at the same cost?