The Keirsey Temperament Sorter says ...

Guardians, are the cornerstone of society, for they are the temperament given to serving and preserving our most important social institutions. Guardians have natural talent in managing goods and services--from supervision to maintenance and supply--and they use all their skills to keep things running smoothly in their families, communities, schools, churches, hospitals, and businesses.

Guardians can have a lot of fun with their friends, but they are quite serious about their duties and responsibilities. Guardians take pride in being dependable and trustworthy; if there's a job to be done, they can be counted on to put their shoulder to the wheel. Guardians also believe in law and order, and sometimes worry that respect for authority, even a fundamental sense of right and wrong, is being lost. Perhaps this is why Guardians honor customs and traditions so strongly--they are familiar patterns that help bring stability to our modern, fast-paced world.

Practical and down-to-earth, Guardians believe in following the rules and cooperating with others. They are not very comfortable winging it or blazing new trails; working steadily within the system is the Guardian way, for in the long run loyalty, discipline, and teamwork get the job done right. Guardians are meticulous about schedules and have a sharp eye for proper procedures. They are cautious about change, even though they know that change can be healthy for an institution. Better to go slowly, they say, and look before you leap.

Guardians make up as much as 40 to 45 percent of the population.

The Four types of Guardians are:

Supervisors (ESTJ) | Protectors (ISFJ) | Inspectors (ISTJ) | Providers (ESFJ)

This is pretty much me to a T, and there's a more in-depth assessment here