the Caucasus (mainly Circassians), Central Asia (mainly Tartars), and Central and Eastern Europe (mainly Slavs [Saqaliba]). In Constantinople, about one-fifth of the population consisted of slaves. The city was a major centre of the slave trade in the 15th and later centuries. Slaves were provided by Tatar raids on Slavic villages but also by conquest and the suppression of rebellions, in the aftermath of which entire populations were sometimes enslaved and sold across the Empire, reducing the risk of future rebellion. The Ottomans also purchased slaves from traders who brought slaves into the Empire from Europe and Africa. It has been estimated that some 200,000 slaves – mainly Circassians – were imported into the Ottoman Empire between 1800 and 1909. In 1908, women slaves were still sold in the Ottoman Empire. German orientalist, Gustaf Dalman, reported seeing slaves in Muslim houses in Aleppo, belonging to Ottoman Syria, in 1899, and that boys could be bought as slaves in Damascus and Cairo in as late as 1909. A slave market for captured Russian and Persian slaves was centred in the Central Asian khanate of Khiva. In the early 1840s, the population of the Uzbek states of Bukhara and Khiva included about 900,000 slaves. Contemporary slavery Even though slavery is now outlawed in every country, the number of slaves today is estimated as between 12 million and 29.8 million. According to a broad definition of slavery, there were 27 million people in slavery in 1999, spread all over the world. In 2005, the International Labour Organization provided an estimate of 12.3 million forced labourers. Siddharth Kara has also provided an estimate of 28.4 million slaves at the end of 2006 divided into three categories: bonded labour/debt bondage (18.1 million), forced labour (7.6 million), and trafficked slaves (2.7 million). Kara provides a dynamic model to calculate the number of slaves in the world each year, with an estimated 29.2 million at the end of 2009. According to a 2003 report by Human Rights Watch, an estimated 15 million children in debt bondage in India work in slavery-like conditions to pay off their family's debts. Slavoj Žižek asserts that new forms of contemporary slavery have been created in the post-Cold War era of global capitalism, including migrant workers deprived of basic civil rights on the Arabian Peninsula, the total control of workers in Asian sweatshops and the use of forced labor in the exploitation