A growing share of computationally and data-intensive research, both inside and outside of academia, requires the involvement and support of computing and data professionals. Yet little is known about the composition of the research computing and data (RCD) workforce. This paper presents the results of a survey (N=563) of RCD professionals' demographic and educational backgrounds, work experience, current positions, job responsibilities, and views of working in the RCD field. We estimate the size of the RCD workforce and discuss how the demographic diversity and distribution of backgrounds of those in the RCD workforce fail to match that of the larger academic and technical workforces. These survey results additionally support the insights of those working in the field concerning the need to recruit a wider variety of professionals into the RCD profession, better define job descriptions and career pathways, and improve institutional recognition for the value of RCD work.