Economic crisis is Europe's profit and loss

The survey also discovered that Greece, where some clubs are struggling to stay afloat, has become a virtual no-go zone for foreign players in their prime because of meagre financial rewards.

"The percentage of players imported from abroad at European level has never been as high as in the current season," said Raffaele Poli, the co-author of the report released by the International Centre for Sports Studies (CIES).

"Of the top 31 division leagues of UEFA member associations we surveyed, 36.1 percent of all squad members grew up in a different national association to that of their employer club."

The migration, which was studied in 2011 and 2012, also showed that the sport is no longer a buffer against the fluctuating fortunes of economics that it once was.

"We often say that football is the last defence against the economic crisis, that it is anti-cyclical," added Poli.

"But it's not the case in Greece. Not only has the level of local players in the Greek league fallen by 15 percent between 2011 and 2012, but the number of Greek players now appearing for foreign clubs has also increased.

"Historically, Greek clubs were attractive to foreigners, focussing on players who were in the latter stages of their careers after having played in the best leagues.

"Now, nationals and foreign players are looking elsewhere."

In Spain, where there has been more of a tradition of developing local players, the effects of the financial crisis are just as damaging.

There were 114 Spaniards wearing the colours of a foreign club in the 31 leagues surveyed in 2011; that figure had risen to 148 last year.

Portuguese players featuring for clubs abroad rose by 41 to stand at 171.

The CIES said the exodus of Spanish talent is partly driven by the commercial muscle enjoyed by Real Madrid and Barcelona.

"They are the two biggest clubs. They negotiate individual television rights which results in a very uneven distribution of wealth while others have only crumbs," said Poli.

"Zaragoza, Mallorca, Deportivo, Malaga and Valencia all have financial difficulties. Suddenly, the foreign labour decreases or at least does not increase."

Brazil remains by far the top exporting country.

However, the overall number of Brazilians has fallen slightly during the last year, from 524 to 515.

Conversely, players from the second most represented origin, France, have significantly increased from 245 to 269.

The study identified that overall expatriate footballers represent more than one quarter of players in all positions, with a record high of 44.3 percent among forwards.