Table 1. The number of data collected by year (1946~2017).

Period	Year	N		Period	Year	N		Period	Year	N
		Article	Editorial			Article	Editorial			Article	Editorial
1	1946	26	0		1971	181	23		1996	126	10
	1947	110	0		1972	229	35		1997	133	16
	1948	80	3	3	1973	491	50	6	1998	122	8
	1949	120	3		1974	179	22		1999	164	7
	1950	69	1		1975	132	12		2000	219	13
	1951	26	1		1976	124	13		2001	188	5
	1952	55	3		1977	139	19		2002	144	13
	1953	76	3		1978	185	16		2003	130	4
	1954	116	8	4	1979	166	22		2004	197	2
	1955	113	10		1980	158	14		2005	219	4
	1956	109	5		1981	160	11		2006	153	2
	1957	147	2		1982	160	19		2007	191	7
	1958	146	10		1983	135	15	7	2008	298	4
	1959	168	9		1984	101	6		2009	371	8
	1960	152	7		1985	108	2
	1961	246	14		1986	103	8		2010	364	12
	1962	257	21		1987	135	8		2011	384	4
	1963	168	11	5	1988	178	8		2012	346	7
	1964	199	20		1989	231	10		2013	349	2
	1965	132	14		1990	82	15
	1966	196	9		1991	84	26		2014	405	14
2	1967	182	9		1992	80	10		2015	471	16
	1968	219	17		1993	96	9		2016	300	5
	1969	114	5		1994	80	6
	1970	166	20		1995	94	14		2017	325	7