Passage: The Lǐ family (李) founded the dynasty, seizing power during the decline and collapse of the Sui Empire. The dynasty was briefly interrupted when Empress Wu Zetian seized the throne, proclaiming the Second Zhou dynasty (690–705) and becoming the only Chinese empress regnant.  In two censuses of the 7th and 8th centuries, the Tang records estimated the population by number of registered households at about 50 million people.  Yet, even when the central government was breaking down and unable to compile an accurate census of the population in the 9th century, it is estimated that the population had grown by then to about 80 million people.  With its large population base, the dynasty was able to raise professional and conscripted armies of hundreds of thousands of troops to contend with nomadic powers in dominating Inner Asia and the lucrative trade-routes along the Silk Road.  Various kingdoms and states paid tribute to the Tang court, while the Tang also conquered or subdued several regions which it indirectly controlled through a protectorate system.  Besides political hegemony, the Tang also exerted a powerful cultural influence over neighboring East Asian states such as those in Japan and Korea.

Question: How many people were in the Tang dinasty in &th century?
50 million