From 1789 to 1815, members of Congress received only a daily payment of $6 while in session. Members received an annual salary of $1,500 per year from 1815 to 1817, then a per diem salary of $8 from 1818 to 1855; since then they have received an annual salary, first pegged in 1855 at $3,000. In 1907, salaries were raised to $7,500 per year, the equivalent of $173,000 in 2010. In 2006, members of Congress received a yearly salary of $165,200. Congressional leaders were paid $183,500 per year. The Speaker of the House of Representatives earns $212,100 annually. The salary of the President pro tempore of the United States Senate for 2006 was $183,500, equal to that of the Party leaders of the United States House of Representatives and Party leaders of the United States Senate. Privileges include having an office and paid staff. In 2008, non-officer members of Congress earned $169,300 annually. Some critics complain congressional pay is high compared with a median American Household income in the United States of $45,113 for men and $35,102 for women. Others have countered that congressional pay is consistent with other branches of government. Another criticism is that members of Congress have access to free or low-cost medical care in the Washington D.C. area.  The petition, "Remove health-care subsidies for Members of Congress and their families", has already gathered over 1,076,000 signatures on the website Change.org.  In January 2014, it was reported that for the first time over half of the members of Congress were millionaires. Congress has been criticized for trying to conceal pay raises by slipping them into a large bill at the last minute. Others have criticized the wealth of members of Congress. Representative Jim Cooper of Tennessee told Harvard professor Lawrence Lessig that a chief problem with Congress was that members focused on lucrative careers as lobbyists after serving––that Congress was a "Farm team for K Street (Washington, D.C.)"––instead of on public service.
Question: By how many dollars did a Congressman's annual salary increase between 1855 and 1907?
Answer: 4500