The purpose of the diversity immigrant visa program (DV program, sometimes called "the green card lottery" or "the visa lottery") is, as the name suggests, to foster legal immigration from countries other than the major sending countries of current immigrants to the United States. Current law weights the allocation of immigrant visas primarily toward individuals with close family in the United States and, to a lesser extent, toward those who meet particular employment needs. The diversity immigrant category was added to the Immigration and Nationality Act (INA) by the Immigration Act of 1990 (P.L. 101-649) to stimulate "new seed" immigration (i.e., to foster new, more varied migration from other parts of the world). The DV program currently makes 50,000 visas available annually to natives of countries from which immigrant admissions were less than 50,000 over the preceding five years combined. The formula for allocating these visas is specified in statute: visas are divided among six global geographic regions, and each region and country is identified as either high-admission or lowadmission based on how many immigrant visas were given to foreign nationals from each region and country over the previous five-year period. Higher proportions of diversity visas are allocated to low-admission regions and countries. The INA limits each country to 7% (3,500, currently) of the total and provides that Northern Ireland be treated as a separate foreign state. Because demand for diversity visas greatly exceeds supply, a lottery system is used to select individuals who may apply for them. Those selected by lottery ("lottery winners"), like all other foreign nationals wishing to come to the United States, must undergo reviews performed by Department of State consular officers abroad and Department of Homeland Security immigration officers upon entry to the United States. These reviews are intended to ensure that the foreign nationals are not ineligible for visas or admission to the United States under the grounds for inadmissibility spelled out in the INA. To be eligible for a diversity visa, the INA requires that a foreign national have at least a high school education or the equivalent, or two years' experience in an occupation that requires at least two years of training or experience. The foreign national or the foreign national's spouse must be a native of one of the countries listed as a foreign state qualified for the diversity visa program. The distribution of diversity visas by global region of origin has shifted over time, with higher shares coming from Africa and Asia in recent years compared to earlier years when Europe accounted for a higher proportion. Of all those admitted through the program from FY1995 (the first year it was in full effect) through FY2017 (the most recent year for which data are available), individuals from Africa accounted for 40% of diversity immigrants, while Europeans accounted for 31% and Asians for 25%. Some argue that the DV program should be eliminated and its visas re-allocated for employment based visas or backlog reduction in various visa categories. Critics of the DV program warn that it is vulnerable to fraud and misuse and is potentially an avenue for terrorists to enter the United States, citing the difficulties of performing background checks in many of the countries whose citizens are eligible for a diversity visa. Critics also argue that admitting immigrants on the basis of their nationality is discriminatory and that the reasons for establishing the DV program are no longer germane. Supporters of the program argue that it provides "new seed" immigrants for a system weighted disproportionately to family-based immigrants from a handful of countries. Supporters contend that fraud and abuse have declined following measures put in place by the State Department, and that the system relies on background checks for criminal and national security matters.