An employee's enthusiasm starts to decline during the first year of employment, research claims.

According to a study by Sirota, overall satisfaction falls 15 per cent to 54 per cent between the second and fifth year for employees between the ages of 25 and 34.

During the same period, the figure falls to 53 per cent in those over the age of 55, suggesting that job satisfaction is not linked only to age, according to the firm.

"Older employees start new jobs with the same hopefulness as younger workers. They have the same fundamental needs," Douglas Klein, president of Sirota.

"Their level of enthusiasm depends on how well their needs are met as they move through the various stages of their employment life-cycle," he added.

Indeed, an earlier study by the organisation found that poor-quality line managers reduced the morale of those working immediately below them.