I often read about the "trends" of the banker's offers but I'm not fully aware exactly when they happened... would a stats person care to elaborate a bit?

I know late 2005 and early 2007 saw very generous offers (both in active play and proveout as some plays found out to their disadvantage!), and the start of season 3 started the run of poor offers... and it's pretty much remained the same ever since, with the odd exception such as Barry yesterday.

But what about during 2006? I can't say I remember much about the banker's offers then, although I often read about how they were poor in Spring 2006 (I think...).

pretty average in May-July 06 I'd say on the whole and mixed spells of average/inflated from Aug/Sept - Dec 07

Yeah I think they were quite *beep* in February/March 2006, which is why some people got so suspicious about the sequences, thinking that the Banker was making crap offers 'cos he knew people had blues. (Although there were some exceptions, such as John G and Benita getting extremely generous offers with blues in their boxes, and Vanessa being forced to the end with £20k in her box.)

Personally I'd say they were at their best just after that, around April 2006, and that lasted until January 2007 when they got stupidly generous and they've never really recovered since.

Late 2005 - largely formula-bound, clear path from very low at the start to very high at the end, made five-box the obvious time to go for the average player on most boards.

Early 2006 definitely had low offers throughout, hence the suspicion of myself and others as daniel4389 points out. They gradually became more generous in the second quarter of 2006, especially the early offers. The late-game offers settled a bit, I think, in the second half of 2006, although proveout lies became a bit more blatant in the run-up to Christmas and this was effectively the first phase of the Wakey Winter of 2006-7, with Noel begging players to win the £250k (hence the huge guilt trips at Ingerlise and Donna). I thought at the time that the first £250k win would cause Noel to ease off; history proved me spectacularly wrong.

When the show first started, the opening offers were extremely low and then became extremely high at 5-box. Mally, for example, had a 6.9k 8-box offer followed by a 54k 5-box offer, and a 145k offer on a final 2 with 100 quid and 250k!
Since then, the banker got better, but is now just as bad the opposite way.

Winter 2006 to early 2007 is my fave dond period and why shouldn't Noel guilt trip them? They squandered 100s of thousands of pounds in their greed for a bit of money, Laura set a shining example how dond is played (yer the final offer was crap but so what, players these days would have took it in a instant). Others need to follow her example and grab the moment with no fear. =) lol.

But why has the Banker varied his offers so much over the years?

Is it to keep things less predictable or does it just vary depending on the run of games. Like at the moment where a lot of games have very bad luck and the Banker thinks (and does) that he can get players cheap. Or that players actually think they are generous offers when they're not and till people recognize that the offers will always stay low.

Probably quite a few reasons. Mostly to keep the show as unpredictible and exciting as possible. Also, each player is different. It's the banker's objective to get the box for as little as possible. If the player is a targetist or cautious, the banker doesn't need to offer as much to get them to deal. If the player is a gambler or genuinely "there to play the game" then it will take a bit more money to get them to deal. I guess part of it depends on how the games have been going previously. If it's been going badly (ie, now), players will be more cautious and expect to win less money.