41.   Tracking computer sales has added up to big money for Dataquest.

42.   Tracking sales proves difficult, because organizations such as Soundscan have not traditionally paid attention to the genre.

43.   While market analysts have yet to begin tracking sales of ad blockers, individual companies report sales are on the rise lately.

44.   And borough officials say tracking toy sales is not a good enough reason for them to bend the law.

45.   Another Internet company hit hard was Ariba, which helps companies track sales on the Web.

46.   Companies that track retail sales also reported gains.

47.   Each list tracks sales at different bookstores.

48.   In September, the Razor was the top-selling toy in the nation based on total sales, according to the NPD Group, which tracks toy sales.

49.   Now they track sales closely, from stockist to retailer.

50.   Polka has traditionally been a niche music market, and it is hard to track sales because the performers often sell more music at concerts than in stores.