Thursday was a day of protest in cities across the nation, with fast food workers calling for the $7.25 minimum wage to more than double, to $15 per hour.Even some of Topeka’s Pizza Hut employees joined the protest, although a cook there said workers would be happy with much less than $15 – even $8 an hour would help, he said.Congress instituted the minimum wage – 25 cents an hour – in 1938 as part of the Fair Labor Standards Act. Since 2009 it has been $7.25 an hour. Adjusted for inflation, the value of minimum wage has been up and down over the years, averaging (in today’s dollars) $6.60 since 1947.