I think mine might be the EB2 category according to the following information source:
http://www.usabal.com/permres/greencardfaq.html#14
Hope this will be helpful for others too.
What is a preference category?
The vast majority of employment-based immigrants fall into either the second preference (EB2) or the third preference (EB3) category.
What is the difference between EB2 and EB3?
Generally, EB2 classification is for people who will work in jobs that require someone with either an advanced degree (for example, a master’s degree or Ph.D.) or its equivalent (i.e., a bachelor’s degree plus at least five years of “progressive” experience). EB3 is for people whose jobs don’t require such education or expertise. Classification is determined not by what education and experience the person actually has, but by what education and experience is necessary for the person’s job as set forth in the labor certification.
What does it matter whether a person is classified as EB2 or EB3?
Every year, quotas allow only a limited number of people to immigrate to the U.S. The quotas depend both on the preference category and the country of one’s birth. The laws do not allow more than a certain number of EB2 and EB3 individuals to immigrate, and each country is limited to a percentage of the total number of each catetgory.
For people from most countries, it makes no difference whether they are classified as EB2 or EB3, because both of these categories are “current” (meaning there is no waiting to immigrate) for most of the world’s countries. Until recently, persons born in India and the PRC, who fell under certain employment-based categories, normally had to wait for their priority dates to become current before filing for AOS.
If an employee has to wait to immigrate, how is the length of the wait calculated?
The employee must wait until his or her “priority date” is current before he or she will be allowed to begin the third step of the immigration process. The priority date is the date the employee’s labor certification application was originally filed (generally, the date the application was received by the state employment security agency).
Every month, the U.S. Department of State tracks the number of people who immigrate from all countries in each preference category. Based on those numbers, it designates certain priority dates for each category as current, and people holding these or older priority dates are eligible to move to the third step of the immigration process.
If an employee has to wait to immigrate, how long might the wait be?
An example can illustrate how the waiting process works. Suppose that a company filed a labor certification application on behalf of a Chinese national in a job requiring a master’s degree on May 1, 1997 (the priority date). The labor certification was approved by DOL on April 1, 1998. The employer then filed an immigrant petition with INS based on the approved labor certification on April 15, 1998, which was approved on August 15, 1998. Because the job the employee holds requires a master’s degree, the employee qualifies for and was given EB2 classification.
When would this employee be eligible to immigrate? In November 1998, the State Department indicated that current priority date for Chinese-born EB2 immigrants was May 22, 1996. This meant that those immigrants whose labor certification applications were filed on or before May 22, 1996 were eligible to immigrate. The employee described above, therefore, would have to wait.
If the difference between the current date and an employee’s priority date is one year, does this mean that the employee’s wait will be one year?
Not necessarily. Priority dates do not advance at the same rate as the calendar. In some months, the date may not move at all; in others, the date might move forward by weeks or even months at a time. Priority dates may even retrogress.