COLUMBIA, Mo. (AP) — A conservative advocacy group’s Missouri chapter is seeking to put what’s expected to be the state’s first gas tax hike in years to a public vote. The secretary of state said Monday that Americans for Prosperity-Missouri’s director filed the referendum petition. Missouri’s Republican-led Legislature last week approved a gradual increase in the state’s 17 cents per gallon gas tax to 29.5 cents over five years. Republican Gov. Mike Parson is expected to sign the bill into law. Missouri voters have repeatedly voted down increases to the gas tax.