(Reuters) - The pace slowed in the third week of enrollment for 2018 Obamacare individual insurance as nearly 800,000 people signed up through the federal government website HealthCare.gov, down about 75,000 people from the previous week, a U.S. government agency reported on Wednesday.   There was an increase, however, in the number of new consumers to the program created by former President Barack Obama, to 220,323 from 208,397 in the previous week, the U.S. Department of Health and Human Services said.  Republican President Donald Trump and lawmakers are trying to undo Obama’s health law but do not have enough votes to repeal it and so must continue to run the insurance program, which offers income-based subsidies. Uncertainty over its future drove 2018 monthly premiums up more than 30 percent on average as insurers such as Anthem Inc, Centene Corp and Molina Healthcare sought to cover higher costs. The nonpartisan Congressional Budget Office has estimated that 11 million will enroll in 2018, up from 2017’s 10 million, even as the period for sign-ups has been cut in half to six weeks and will end on Dec. 15. Total sign-ups for Obamacare individual insurance in the 39 states that use HealthCare.gov reached 2.28 million during the first three weeks of enrollment. The figures do not include enrollment in Washington, D.C. or the 11 states including New York and California that run their own enrollment and websites.  Among the states using HealthCare.gov with the highest number of individuals signing up were Florida, 498,168; Texas, 271,737; North Carolina, 138,932; Georgia, 119,968; and Pennsylvania, 101,286, the agency said. 