Dear …
I want to congratulate you on the sales successes we are seeing from __ (you/your department)__ over this past __(month/quarter/year)__. The latest numbers are in and I am happy to inform you that your new sales figures for the period of __(date to date)__ amounted to __($ amount)__. This represents an increase of __(%)__ over the preceding __(month/quarter/year/period)___.
The company is very pleased with these numbers and I want you to know that we appreciate all your efforts. Your enthusiasm and hard work __(along with the ability to motivate your team)__ has resulted in a significant increase in sales. You are __(all)__ to be highly commended for this achievement. Congratulations!
Sincerely,