In this photo, a receptionist switches off her equipment at the end of a post office 'confravision' in Euston Tower, London, Sept. 28, 1971. Getty Images / Hulton Archive

Successful business people are only as good as the team and people they surround themselves with and that is why Administrative Professionals’ Day is important, as it is a way to thank those who deserve it, to the people who work hard behind the scenes.

The last full week of April is observed every year as Administrative Professionals' Week. This year, the Administrative Professionals Day is on Saturday. Though it is not a national holiday, it is observed in most parts of the United States.

The history of the day goes back to World War II (1939-1945) when there was a serious shortage of skillful administrative personnel in the U.S. However, the official period of celebration started in 1952, according to International Association of Administrative Professionals website.

So, here is a list of 10 quotes that you can share with your assistants to show your gratitude and let them know how special they really are.

1. "No one who achieves success does so without acknowledging the help of others. The wise and confident acknowledge this help with gratitude." – Unknown

2. "No one is more cherished in this world than someone who lightens the burden of another. Thank you." – Unknown

3. "Let us be grateful to people who make us happy; they are the charming gardeners who make our souls blossom." – Marcel Proust

4. "I would maintain that thanks are the highest form of thought and that gratitude is happiness doubled by wonder." - G.K. Chesterton

5. "Appreciation is a wonderful thing. It makes what is excellent in others belong to us as well." - Voltaire

6. "What sunshine is to flowers, smiles are to humanity. These are but trifles, to be sure; but, scattered along life's pathway, the good they do is inconceivable." - Joseph Addison

7. "Appreciate everything your associates do for the business. Nothing else can quite substitute for a few well-chosen, well-timed, sincere words of praise. They're absolutely free and worth a fortune." - Sam Walton

8. "Happy is the man with a wife to tell him what to do and a secretary to do it." - Lord Mancroft

9. "If you take a bunch of superstars and put them in a room where they don’t have their assistants and entourage, it’s funny to see what happens." - Daryl Hall

10. "Appreciation is the highest form of prayer, for it acknowledges the presence of good wherever you shine the light of your thankful thoughts." - Alan Cohen