In January 2019, • labor force participation in the United States was 62.3%. • official unemployment was 4.1%. • the proportion of short-term unemployment (14 weeks or less) in that month on average was 68.9%. • moderately long-term unemployment (15-26 weeks) was 12.7%. • very long-term unemployment (27 weeks or longer) was 18.4%. Based on these statistics, what proportion of the labor force was unemployed very long term in January 2019, to the nearest tenth of a percent?