|Year|Political Rights|Civil Liberties|Status|President|
|---|---|---|---|---|
|1972|6|6|Not Free|Hamani Diori|
|1973|6|6|Not Free|Hamani Diori|
|1974|7|6|Not Free|Hamani Diori|
|1975|7|6|Not Free|Seyni Kountché|
|1976|7|6|Not Free|Seyni Kountché|
|1977|7|6|Not Free|Seyni Kountché|
|1978|7|6|Not Free|Seyni Kountché|
|1979|7|6|Not Free|Seyni Kountché|
|1980|7|6|Not Free|Seyni Kountché|
|1981|7|6|Not Free|Seyni Kountché|
|1982|7|6|Not Free|Seyni Kountché|
|1983|7|6|Not Free|Seyni Kountché|
|1984|7|6|Not Free|Seyni Kountché|
|1985|7|6|Not Free|Seyni Kountché|
|1986|7|6|Not Free|Seyni Kountché|
|1987|7|6|Not Free|Seyni Kountché|
|1988|6|6|Not Free|Ali Saibou|
|1989|7|6|Not Free|Ali Saibou|
|1990|6|5|Not Free|Ali Saibou|
|1991|6|5|Partly Free|Ali Saibou|
|1992|5|4|Partly Free|Ali Saibou|
|1993|3|4|Partly Free|Ali Saibou|
|1994|3|5|Partly Free|Mahamane Ousmane|
|1995|3|5|Partly Free|Mahamane Ousmane|
|1996|7|5|Not Free|Mahamane Ousmane|
|1997|7|5|Not Free|Ibrahim Baré Maïnassara|
|1998|7|5|Not Free|Ibrahim Baré Maïnassara|
|1999|5|5|Partly Free|Ibrahim Baré Maïnassara|
|2000|4|4|Partly Free|Mamadou Tandja|
|2001|4|4|Partly Free|Mamadou Tandja|
|2002|4|4|Partly Free|Mamadou Tandja|
|2003|4|4|Partly Free|Mamadou Tandja|
|2004|3|3|Partly Free|Mamadou Tandja|
|2005|3|3|Partly Free|Mamadou Tandja|
|2006|3|3|Partly Free|Mamadou Tandja|
|2007|3|4|Partly Free|Mamadou Tandja|
|2008|3|4|Partly Free|Mamadou Tandja|
|2009|5|4|Partly Free|Mamadou Tandja|
|2010|5|4|Partly Free|Mamadou Tandja|
|2011|3|4|Partly Free|Salou Djibo|

Question: how many years was it before the first partly free status?
Answer: 18