What is referred to by 'accumulated over time'?

Based on the clue 'accountants try to do this keep revenue related e...', what is the answer? What is associated with: accounting for half of all us exports in 1855 this crop was king? Based on the clue 'accounts of these experiences often include being ...', what is the answer? What is referred to by 'accruable accrid accommodable'? Based on the clue 'accurate to 750 yards the m21 was used in vietnam ...', what is the answer? Based on the clue 'accusative for direct objects of verbs dative for...', what is the answer? What is associated with: accused by some of ruining girls self esteem this bestselling toy of all time turned 40 in 199… Based on the clue 'accused jfk assassin lee harvey oswald was himself...', what is the answer?