Each year there is an official survey of attitudes within the armed forces, called The 2015 Armed Forces Continuous Attitude Survey and the BBC in a very slim report:
The rate of personnel planning to leave, or who have given their notice, increased from 16% in 2011 to 25% now. Those planning to stay in the service for as long as they could also fell from 41% in 2011 to 34% now.
However, the survey of 11,877 personnel also found there had been an increase in morale, with 45% rating their morale as high, compared with 41% in 2014
Link:http://www.bbc.co.uk/news/uk-32851668