price of piecework done whereas the company is liable to supply the necessary production materials to the "abons". Most manufacturers have since opted to have their workers working under the roof of their own factories, to maintain quality standards. Nowadays, only a few kretek manufacturers make use of the abon system. During the period from 1960 until 1970 and the earlier days of the New Order regime, kreteks became a national symbol against "white cigarettes". In the mid-1980s, the number of machine-produced cigarettes exceeded that of hand-rolled ones. One of the largest income sources of Indonesia, the kretek industry comprises 500 large and small manufacturers employing a total of around 10 million people. Since 2009, kreteks are not legal for sale in the United States. A variation of the kretek is sold: "cigars" that are similar in size and shape to the original kreteks, also with a filter and the original tobacco/clove blend, but in a tobacco-based paper. Structure and ingredients The quality and variety of tobacco play an important role in kretek production. One kretek brand can contain more than 30 types of tobacco. Minced dried clove buds weighing about 1/3 of the tobacco blend are added. Sometimes the last process that machine-made or hand-rolled kreteks go through is the spraying of sweetener at the butt end of the cigarette. Health effects Djarum Black cigarettes sold in Europe, South Africa and South American countries have 10–12 mg tar and 1 mg nicotine, as indicated on the pack. This level of tar and nicotine is comparable to the majority of other regular or "full-flavor" cigarettes available. Djarum Black cigarettes produced for consumption in Indonesia contain a significantly higher quantity of tar and nicotine, 25 mg and 1.6 mg respectively. In Canada, Djarum Black cigarettes are listed as containing 44.2–86 mg of tar and 1.73–3.24 mg of nicotine, a significant amount more than most other cigarettes. The venous plasma nicotine and carbon monoxide levels from 10 smokers were tested after smoking kreteks and were found to be similar to non-clove brands of cigarettes, such as Marlboro. Rats were given equal inhalation doses of conventional tobacco cigarettes and kreteks over a short period. Those that had inhaled kreteks did not appear to show worse health effects compared to those that had inhaled conventional cigarettes. The study was repeated with a 14-day exposure and kreteks again did not produce worse health effects than