Anniversary messages began being sent out by the Royal Household on a regular basis in 1917. This was also the first year that statistics were recorded.
Changes in the numbers of anniversary messages sent out reflect changes in society over the last 90 years.
The figures show that people are living longer. In 1952 less than 3,000 congratulatory messages were sent out. But in 2011, the total number of 100th birthday messages alone was 9,736, with 30,359 messages for diamond weddings.
This reflects the fact that people are healthier, due to higher living standards. More and more people are reaching ages which in previous decades were very rare. In 2011, 917 people received messages for 105th birthdays and above. Figures from 1917 record only seven men and 17 women receiving 100th birthday greetings sent on behalf of King George V. In 1952, just 255 centenarians received a congratulatory message.
The oldest ever recipient of a message from The Queen was a Canadian gentleman, who reached the age of 116 in December 1984, whilst the oldest British recipient was 115, the oldest woman in Britain at the time.
Occasionally, twins reach their milestone together. In 2006, three sets of twin sisters and in 2007, twin brothers reaching 100 were recorded by Buckingham Palace. The Anniversaries Office, which is responsible for sending out messages, ensures that each twin receives a slightly different greeting, aware that they will generally be together on their big day and will open their cards at the same time.
Some centenarians have been lucky enough to receive more than one message from The Queen: one congratulating them on their 100th birthday and another for their Diamond (60th) and/or Platinum (70th) wedding anniversaries for which messages are also sent.
One couple, Percy and Florence Arrowsmith, received cards for their 60th and 70th anniversaries, plus individual 100th birthday greetings. Mr Arrowsmith received yet another when he reached 105. The couple eventually reached their 80th (oak) wedding anniversary, and so would have been eligible for another nine cards.
The end of World War Two is clearly reflected in the message statistics. In 2005 nearly 6,000 more diamond wedding messages were sent out than in 2004. This is a result of the end of the war 60 years previously, which resulted in a large number of marriages as soldiers returned from abroad.
The longest period of marriage for which The Queen has sent a congratulatory message is 83 years. In 2006 The Queen sent a message to the world's longest married couple, Mr. and Mrs. William Jones, whose wedding took place in Pontypridd, South Wales, in February 1923.
The message statistics also show some interesting links to particular times of the year, particularly Bank Holidays. Sixty years ago, Easter and Spring Bank Holidays were popular times to get married.
This means that nowadays the Anniversaries Office gets very busy around Bank Holiday times, making sure that couples celebrating their diamond weddings receive their congratulatory card on time.
During her reign The Queen has sent approximately 110,000 telegrams and messages to centenarians in the UK and the Commonwealth.
In the same period more than 520,000 telegrams and messages have been sent by The Queen to UK and Commonwealth couples celebrating their diamond wedding anniversary.
