the breakdown of aes 2019s gross margin for the years ended december 31 , 2000 and 1999 , based on the geographic region in which they were earned , is set forth below. .
* includes venezuela and colombia . selling , general and administrative expenses selling , general and administrative expenses increased $ 11 million , or 15% ( 15 % ) , to $ 82 million in 2000 from $ 71 million in 1999 . selling , general and administrative expenses as a percentage of revenues remained constant at 1% ( 1 % ) in both 2000 and 1999 . the increase is due to an increase in business development activities . interest expense , net net interest expense increased $ 506 million , or 80% ( 80 % ) , to $ 1.1 billion in 2000 from $ 632 million in 1999 . interest expense as a percentage of revenues remained constant at 15% ( 15 % ) in both 2000 and 1999 . interest expense increased primarily due to the interest at new businesses , including drax , tiete , cilcorp and edc , as well as additional corporate interest costs resulting from the senior debt and convertible securities issued within the past two years . other income , net other income increased $ 16 million , or 107% ( 107 % ) , to $ 31 million in 2000 from $ 15 million in 1999 . other income includes foreign currency transaction gains and losses as well as other non-operating income . the increase in other income is due primarily to a favorable legal judgment and the sale of development projects . severance and transaction costs during the fourth quarter of 2000 , the company incurred approximately $ 79 million of transaction and contractual severance costs related to the acquisition of ipalco . gain on sale of assets during 2000 , ipalco sold certain assets ( 2018 2018thermal assets 2019 2019 ) for approximately $ 162 million . the transaction resulted in a gain to the company of approximately $ 31 million . of the net proceeds , $ 88 million was used to retire debt specifically assignable to the thermal assets . during 1999 , the company recorded a $ 29 million gain ( before extraordinary loss ) from the buyout of its long-term power sales agreement at placerita . the company received gross proceeds of $ 110 million which were offset by transaction related costs of $ 19 million and an impairment loss of $ 62 million to reduce the carrying value of the electric generation assets to their estimated fair value after termination of the contract . the estimated fair value was determined by an independent appraisal . concurrent with the buyout of the power sales agreement , the company repaid the related non-recourse debt prior to its scheduled maturity and recorded an extraordinary loss of $ 11 million , net of income taxes. .
2000 % of Revenue 1999 % of Revenue % change
North America $844 million 25% $649 million 32% 30%
South America $416 million 36% $232 million 28% 79%
Caribbean* $226 million 21% $75 million 24% 201%
Europe/Africa $371 million 29% $124 million 29% 199%
Asia $138 million 22% $183 million 37% (26%)
north america 2000 $ 844 million % (  % ) of revenue 25% ( 25 % ) 1999 $ 649 million % (  % ) of revenue 32% ( 32 % ) % (  % ) change 30% ( 30 % )
south america $ 416 million 36% ( 36 % ) $ 232 million 28% ( 28 % ) 79% ( 79 % )
caribbean* $ 226 million 21% ( 21 % ) $ 75 million 24% ( 24 % ) 201% ( 201 % )
europe/africa $ 371 million 29% ( 29 % ) $ 124 million 29% ( 29 % ) 199% ( 199 % )
asia $ 138 million 22% ( 22 % ) $ 183 million 37% ( 37 % ) ( 26% ( 26 % ) )
what was the gross margin change in basis points for south america?