Is penalty success rate increasing over the time?

Question

As time goes by, the knowledge of football increases. And we learn more and more ( at least on paper) about how to shoot penalty better.

Do the insights actually help football players in taking penalty? Does penalty success rate increase over time, much like how aviation accident is brought down over time? Or is it just an arm race with no side is apparently winning?

Any studies on the penalty success rate as a function of time?

Answer 1

Considering Transfermarkt data on Premier League since 1992, I would say that the success rate has decreased over years.

Year | Success rate (%)
_______________________
1992 |  93.4
1993 |  97.6
1994 |  91.7
1995 |  94.5
1996 |  95.3
1997 |  93.4
1998 |  90.7
1999 |  97.1
2000 |  91.4
2001 |  90.4
2002 |  96.2
2003 |  95.7
2004 |  92.3
2005 |  77.0
2006 |  79.1
2007 |  78.2
2008 |  78.8
2009 |  78.9
2010 |  78.6
2011 |  74.2
2012 |  80.0
2013 |  83.9
2014 |  76.8
2015 |  81.3
2016 |  76.4
2017 |  70.0
2018 |  81.6
2019 |  80.6

For some reason, it drastically dropped between 2004 and 2005, and it was around 93% before and 78% lately.

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Transfermarkt on Bundesliga since 1992:

Year | Success rate (%)
_______________________
1992 |  80.3
1993 |  84.7
1994 |  83.1
1995 |  79.2
1996 |  79.7
1997 |  73.2
1998 |  71.6
1999 |  75.8
2000 |  80.0
2001 |  72.5
2002 |  71.6
2003 |  77.6
2004 |  86.4
2005 |  73.1
2006 |  68.2
2007 |  78.0
2008 |  76.6
2009 |  78.2
2010 |  68.7
2011 |  86.8
2012 |  75.9
2013 |  73.6
2014 |  81.7
2015 |  79.1
2016 |  72.4
2017 |  73.1
2018 |  81.3
2019 |  78.1

It's hard to find a pattern on the German statistics. They are roughly around 77%, with ups and downs equally distributed.