When Spurs signs a player we generally know how much has been paid in transfer fees, the figures from www.soccerbase.com are a good source.
The club has to pay the transfer fee to the selling club. In the club accounts it then has to report how much it views each player's worth has declined each year. So for example Gareth Bale for a reputed £10m on a five year contract costs the club £2m per year. This is what is reported as 'amortisation' in the club accounts. At the end of the contract the player can just leave on a 'free' so he is viewed as potentially no worth to the business after that.
This only covers the costs for players bought in. So Ledley King, for example, does not have any effect on the amortisation costs of the club, as he was never bought from another club. Also once a player has finished his initial contract he stops being counted. So Robbie Keane for example had no effect.
The annual amount the club are paying out for players looked to have settled down at about £11-12m per season up to 2006 and then shot up.
The slight blip in 2003 came from the club just writing off the values of Rebrov and Thatcher. This was combined hit of £7.3m, £5.1m on Rebrov, £2.1m on Thatcher.
The huge leap in the 2008 figures comes from the purchase of players during 2006-2007 and then at the start of the 2007-2008 season. The £37m figure is huge, and is probably not sustainable without a steady income at the level of the last two seasons which had European football, and in 2008 the League Cup win.
