an average of 7.1 in 2000 . the top 100 largest clients used an average of 11.3 products in 2001 , up from an average of 11.2 in 2000 . state street benefits significantly from its ability to derive revenue from the transaction flows of clients . this occurs through the management of cash positions , including deposit balances and other short-term investment activities , using state street 2019s balance sheet capacity . significant foreign currency transaction volumes provide potential for foreign exchange trading revenue as well . fee revenue total operating fee revenuewas $ 2.8 billion in 2001 , compared to $ 2.7 billion in 2000 , an increase of 6% ( 6 % ) . adjusted for the formation of citistreet , the growth in fee revenue was 8% ( 8 % ) . growth in servicing fees of $ 199million , or 14% ( 14 % ) , was the primary contributor to the increase in fee revenue . this growth primarily reflects several large client wins installed starting in the latter half of 2000 and continuing throughout 2001 , and strength in fee revenue from securities lending . declines in equity market values worldwide offset some of the growth in servicing fees . management fees were down 5% ( 5 % ) , adjusted for the formation of citistreet , reflecting the decline in theworldwide equitymarkets . foreign exchange trading revenue was down 5% ( 5 % ) , reflecting lower currency volatility , and processing fees and other revenue was up 21% ( 21 % ) , primarily due to gains on the sales of investment securities . servicing and management fees are a function of several factors , including the mix and volume of assets under custody and assets under management , securities positions held , and portfolio transactions , as well as types of products and services used by clients . state street estimates , based on a study conducted in 2000 , that a 10% ( 10 % ) increase or decrease in worldwide equity values would cause a corresponding change in state street 2019s total revenue of approximately 2% ( 2 % ) . if bond values were to increase or decrease by 10% ( 10 % ) , state street would anticipate a corresponding change of approximately 1% ( 1 % ) in its total revenue . securities lending revenue in 2001 increased approximately 40% ( 40 % ) over 2000 . securities lending revenue is reflected in both servicing fees and management fees . securities lending revenue is a function of the volume of securities lent and interest rate spreads . while volumes increased in 2001 , the year-over-year increase is primarily due to wider interest rate spreads resulting from the unusual occurrence of eleven reductions in the u.s . federal funds target rate during 2001 . f e e r e v e n u e ( dollars in millions ) 2001 ( 1 ) 2000 1999 ( 2 ) change adjusted change 00-01 ( 3 ) .

2001 ( 1 ): servicing fees: 1624
management fees: 511
foreign exchange trading: 368
processing fees and other: 329
total fee revenue: 2832
2000: servicing fees: 1425
management fees: 581
foreign exchange trading: 387
processing fees and other: 272
total fee revenue: 2665
1999 ( 2 ): servicing fees: 1170
management fees: 600
foreign exchange trading: 306
processing fees and other: 236
total fee revenue: 2312
change 00-01: servicing fees: -14
management fees: -12
foreign exchange trading: -5
processing fees and other: 21
total fee revenue: 6
adjusted change 00-01 ( 3 ): servicing fees: -14
management fees: -5
foreign exchange trading: -5
processing fees and other: 21
total fee revenue: 8

( 1 ) 2001 results exclude the write-off of state street 2019s total investment in bridge of $ 50 million ( 2 ) 1999 results exclude the one-time charge of $ 57 million related to the repositioning of the investment portfolio ( 3 ) 2000 results adjusted for the formation of citistreet 4 state street corporation .

Questions:
what was the change in the servicing fees from 1999 to 2000?
and what were those fees in 1999?
how much, then, does that change represent in relation to these 1999 servicing fees, in percentage?

Answers:
255
1170
21.7%