Changes
The first program was DV-1995, and the following 13 countries were ineligible from the start: Canada, China (mainland), Dominican Republic, El Salvador, Haiti, India, Jamaica, Mexico, Philippines, South Korea, Taiwan, United Kingdom (except Northern Ireland) and its dependent territories, and Vietnam.
Changes to the list of countries over the years include the following:
DV-1996: Colombia now ineligible.
DV-1998: Poland now ineligible.
DV-2002: Poland and Taiwan now eligible, Pakistan ineligible.
DV-2004: East Timor added, eligible.
DV-2005: Russia now ineligible.
DV-2007: Poland again ineligible.
DV-2008: Brazil and Peru now ineligible; Serbia and Montenegro listed separately, both eligible.
DV-2009: Ecuador and Guatemala now ineligible.
DV-2010: Russia now eligible; Kosovo added, eligible.
DV-2013: Poland again eligible, Bangladesh now ineligible; South Sudan added, eligible.
DV-2014: Guatemala again eligible.
DV-2015: Nigeria will become ineligible, as per the recently released 2012 immigration statistics.[5]
The large number of changes for DV-2002 was due to a three-year gap between the publication of the 1998 and 1999 immigration statistics. In other words, DV-2001 was still using the statistics from the five-year period from 1994 to 1998 to determine country eligibility. As immigration has increased, the number of ineligible countries has risen, from 13 for DV-1995 to 18 now. Colombia, Pakistan, Brazil, Peru, Ecuador, and Bangladesh have been added since 1995 and are currently ineligible, while Taiwan is the only country which was ineligible in 1995 but eligible now due to decreasing immigration.
Russia fell below the ineligibility limit for DV-2010[6] due to a combination of a sharp dropoff in adoptions (from 5,878 in 2004 to 2,301 in 2007) and the unusual bureaucratic quirk of large numbers of Russian immigrants being allocated to "Soviet Union (former)" rather than Russia in 2006 and 2007. Similarly, Guatemala was ineligible from 2009 to 2013 due to a wave of adoptions from that country, and Poland was ineligible for two unconnected periods (1998 to 2001, and 2007 to 2012) due in the latter case to DHS' effort to reduce a backlog of adjustment of status applications.

http://en.wikipedia.org/wiki/Diversity_Immigrant_Visa#Changes