What makes the stamp act a primary source?​

On March 22, 1765, the British Parliament passed the "Stamp Act" to help pay for British troops stationed in the colonies during the Seven Years’ War. The act required the colonists to pay a tax, represented by a stamp, on various forms of papers, documents, and playing cards. It was a direct tax imposed by the British government, without the approval of the colonial legislatures and was payable in hard-to-obtain British sterling, rather than colonial currency. Further, those accused of violating the Stamp Act could be prosecuted in Vice-Admiralty Courts, which had no juries and could be held anywhere in the British Empire.

Explanation:

the answer is "by providing data about careers and annual mean wages"