We measure how workers use genAI in their jobs using a nationally representative survey that links genAI use to detailed tasks. GenAI currently assists a broad range of work, with at least one in five workers using genAI in 80% of occupations and 40% of job tasks. Yet in most of these cases adoption rates remain below 50%, with some individuals systematically adopting genAI for more tasks than others who perform similar work. As a result, although genAI “exposure” measures correlate positively with adoption, they explain only about half of the variation across workers. The nature of genAI use also varies across occupations, with workers in some occupations using it mainly for high-expertise work and others for low-expertise work. Survey-based task shares differ systematically from estimates from genAI platform chat-log data, primarily because chat data overclassify basic, generic tasks relative to the ONET framework. We organize our findings into occupation- and task-level adoption indexes, providing an input for research on the labor market effects of genAI.