20.3 Use the patent data given in Table 12.1, which can be downloaded from the book’s website. Treating the number of patents granted in year 1991 as the dependent variable and the data on R&D expenditure for 1991 and the industry and country dummies as regressors, estimate the 20th, 60th and 75th quantile regressions. Since the regressand is a count variable, use the qcount command in Stata to estimate these quantile regressions, called the count quantile regressions, and interpret your results.