The second one is better — because you don’t need “numbers of” — but the sentence is still ambiguous because of “highest.” Without “highest,” sentence 2 makes perfect sense: it states the amount of sales in 1999 in Switzlerland of fairtrade bananas and coffee. Adding “highest” only makes sense if you are comparing several things — such as trying to say that of all European countries, the sales were highest in Switzerland, or that of all years the sales were highest in 1999.