| CV-HELIOS
NETWORK NUMBER OF CV-OBSERVATIONS PER YEAR |
|
| Year | Obs. Total |
| 1981 | 88 |
| 1982 | 376 |
| 1983 | 220 |
| 1984 | 269 |
| 1985 | 362 |
| 1986 | 518 |
| 1987 | 1447 |
| 1988 | 1716 |
| 1989 | 1728 |
| 1990 | 931 |
| 1991 | 1566 |
| 1992 | 1814 |
| 1993 | 1721 |
| 1994 | 2956 |
| 1995 | 3277 |
| 1996 | 3822 |
| 1997 | 4176 |
| 1998 | 5651 |
| 1999 | 6351 |
| 2000 | 6308 |
| 2001 | 6542 |
| 2002 | 6248 |
| 2003 | 8021 |
| 2004 | 7427 |
| 2005 | 7019 |
| 2006 | 7481 |
| 2007 | 8480 |
| 2008 | 9166 |
| 2009 | 9352 |
| 2010 | 8073 |
| 2011 | 6643 |
| 2012 | 6241 |
| 2013 | 5590 |
| 2014 | 5822 |
| 2015 | 5861 |
| 2016 | 6104 |
| 2017 | 5899 |
| 2018 | 7573 |
| 2019 | 8132 |
| 2020 | 9176 |
| 2021 | 7327 |
| 2022 | 6295 |
| 2023 | 5984 |
| 2024 | 4722 |
| 2025 | |