*3.2. Country-by-Country Ranking*

The revised applications are also classified according to their location, taking into account the fields of knowledge (Figure 5).

There are 34 countries where the RULA method has been used. The USA stands out with 23 studies, followed by Iran with 21, Malaysia with 17, India with 16, Portugal with 15, Brazil with 12 and Canada and the United Kingdom with 11. All other countries have 10 or fewer research studies. Eight locations have a single publication: Saudi Arabia, Japan, Mexico, Poland, Slovenia, Sweden, Tunisia and Venezuela (Figure 5).

In addition to the USA having the largest number of studies, it is also the country where the most knowledge categories have been covered. This comprises a total of 10 areas. "Human health and social work activities" stand out with nine studies, followed by "Manufacturing" with three (Figure 5). Both categories match the ones that have the most published studies at the general level (Figure 4 and Table 2).

The places following the USA are Turkey, Italy, Iran, India and Brazil, with seven different locations. In all of them, except Italy, the largest number of publications also corresponds to "Manufacturing". Iran stands out with 11 studies in this category.

**Figure 5.** Number of studies classified by knowledge categories and countries: Agriculture, forestry and fishing (**A**); Mining and quarrying (**B**); Manufacturing (**C**); Water supply; sewerage, waste management and remediation activities (**D**); Construction (**E**); Wholesale and retail trade; repair of motor vehicles and motorcycles (**F**); Transportation and storage (**G**); Accommodation and food service activities (**H**); Information and communication (**I**); Financial and insurances activities (**J**); Professional, scientific and technical activities (**K**); Administrative and support service activities (**L**); Public administration and defiance; compulsory social security (**M**); Education (**N**); Human health and social work activities (**O**); Arts, entertainment and recreation (**P**); Other service activities (**Q**); Activities of households as employers; undifferentiated goods and services producing activities of households for own use (**R**); and Other scopes not previously included (**S**).

Countries such as Venezuela, Tunisia, Sweden South Africa, Slovenia, Poland, Mexico, Japan and Saudi Arabia only cover one area (Figure 5).

The United Kingdom is the location where the RULA method originated. However, it is not a place where it has been most applied, as only 11 studies have been performed there. The method originated with assessments carried out on workers in the industry [20]. Despite this, RULA has not been widely used in industry in the United Kingdom; it presents only three studies. "Human health and social work activities" stands out with five publications (Figure 5).

Figure 6 shows the different countries according to the frequency of the published studies.

**Figure 6.** Map with frequencies.
