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Table 3

Percentage of Type I ionospheric storms and Type II ionospheric storms observed by the AIS-INGV ionosonde at the Ionospheric Observatory of Rome during the minimum of solar activity at the turn of solar cycles 21–22, 22–23 and 23–24.

Year Percentage of Type I storms Percentage of Type II storms (%)
1985 3.9% 5.2
1986 1.4% 13.3
1987 8.9 10.3
1995 8.3 0.0
1996 3.7 2.8
1997 6.9 9.9
2007 4.6 1.8
2008 5.2 7.8
2009 3.6 0.0

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