Book distribution trends by year.
| 2020 |
| 665 |
| 8 | 2019 | - | - | 2019 | 756 |
| 9 | 2018 | - | - | 2018 | 699 |
| 10 | 2017 | - | - | 2017 | 679 |
| 11 | 2016 | - | - | 2016 | 755 |
| 12 | 2015 | - | - | 2015 | 709 |
| 13 | 2014 | - | - | 2014 | 685 |
| 14 | 2013 | - | - | 2013 | 633 |
| 15 | 2012 | - | - | 2012 | 582 |
| 16 | 2011 | - | - | 2011 | 635 |
| 17 | 2010 | - | - | 2010 | 308 |
| 18 | 2009 | - | - | 2009 | 313 |
| 19 | 2008 | - | - | 2008 | 234 |
| 20 | 2007 | - | - | 2007 | 234 |
| 21 | 2006 | - | - | 2006 | 231 |
| 22 | 2005 | - | - | 2005 | 225 |
| 23 | 2004 | - | - | 2004 | 188 |
| 24 | 2003 | - | - | 2003 | 190 |
| 25 | 2002 | - | - | 2002 | 190 |
| 26 | 2001 | - | - | 2001 | 171 |
| 27 | 2000 | - | - | 2000 | 168 |
| 28 | 1999 | - | - | 1999 | 181 |
| 29 | 1998 | - | - | 1998 | 272 |
| 30 | 1997 | - | - | 1997 | 327 |
| 31 | 1996 | - | - | 1996 | 357 |
| 32 | 1995 | - | - | 1995 | 340 |
| 33 | 1994 | - | - | 1994 | 329 |
| 34 | 1993 | - | - | 1993 | 353 |
| 35 | 1992 | - | - | 1992 | 360 |
| 36 | 1991 | - | - | 1991 | 324 |
| 37 | 1990 | - | - | 1990 | 237 |
| 38 | 1989 | - | - | 1989 | 150 |
| 39 | 1988 | - | - | 1988 | 32 |
| 40 | 1987 | - | - | 1987 | 37 |
| 41 | 1986 | - | - | 1986 | 119 |
| 42 | 1985 | - | - | 1985 | 143 |
| 43 | 1984 | - | - | 1984 | 132 |
| 44 | 1983 | - | - | 1983 | 118 |
| 45 | 1982 | - | - | 1982 | 100 |
| 46 | 1981 | - | - | 1981 | 95 |
| 47 | 1980 | - | - | 1980 | 58 |
| 48 | 1979 | - | - | 1979 | 80 |