Thank you sentence ?

Please help me with the following , i want to thank one if our teams from the office for their continious assistance and cooperation in impelementing a information policy as it has ended.

"Thank you for your continious assistance and cooperation , it is highly appreciated"

As the process has ended and they gave a lot of efforts for their part in the policy , i want to thank them for the work that they have done , please suggest how can i formulate in a professional way the short thank you letter.