Which sentence sounds the best? [on hold]

Which sentence sounds the best? [on hold]

I want to use the word "efficient" in a sentence that describes myself.
Here is what I have so far:
I can work efficiently
I am an efficient worker
I know how to work efficiently
I have a proven track record of being an efficient worker
I constantly push/motivate myself to work efficiently
Which sentence sounds the best and is grammatically correct?
Thanks!