year,facilities
1988,19310
1989,21027
1990,21956
1991,21266
1992,20879
1993,20155
1994,19670
1995,18132
1996,17540
1997,16697
1998,18125
1999,17785
2000,18228
2001,19111
2002,18636
2003,18116
2004,18035
2005,17837
2006,17314
2007,17041
2008,16927
2009,16239
2010,16187
2011,16365
2012,16344
2013,16509
2014,16545
2015,16495
2016,16307
2017,16160