Each month, annual preferences and foreign state limitations are subdivided by the Visa Office into monthly portions based on the applicants reported at consular posts and CIS Offices. If there is a sufficient amount of visas in a category to supply the demand then that category is considered “current” but when the demand over-exceeds the allotted supply of visas the category is considered “oversubscribed.” This is when a visa cut-off date is established, the cut-off date is the “priority date of the first documentarily qualified applicant would could not be accommodated for a visa number.”
To view the chart with the estimated total number of visas available for each employment preference category and country for fiscal year 2011 visit: http://www.travel.state.gov/pdf/EmploymentDemandUsedForCutOffDates.pdf