McKinley, a large consulting company in UK, has a consulting staff consisting of 400 consultants at the rank of "associate". On average, a consultant remains at the associate level for 2 years. After this time, 30% are promoted to "manager" and 70% leave the company. In order to maintain the consultant staff at the average level of 400 associates, how many new consultant does Mckinley have to hire reach year at the associate level?