Calculate selection as percentage of total - spotfire

Question

I need to let users select some (1+) categories and then calculate % of values in that category compared to all values in current filtering.
I could achieve to show marked vs total using subsets, however I can't write an expression across subsets.
e.g. in first column I would need to get result 6 / 20 = 0.3
Notes
I need a generic solution, not one based on structure of my sample dataset
Total should be total of current filtering, not total of all data
Sample data:
country
year
category
FR
2001
4
FR
2002
3
FR
2003
5
FR
2004
1
FR
2005
3
FR
2006
2
FR
2007
3
FR
2008
3
FR
2009
2
FR
2010
1
FR
2011
2
FR
2012
3
FR
2013
5
FR
2014
3
FR
2015
3
FR
2016
2
FR
2017
5
FR
2018
2
FR
2019
4
FR
2020
5
DE
2001
4
DE
2002
2
DE
2003
2
DE
2004
2
DE
2005
3
DE
2006
5
DE
2007
3
DE
2008
4
DE
2009
3
DE
2010
4
DE
2011
4
DE
2012
2
DE
2013
4
DE
2014
4
DE
2015
4
DE
2016
2
DE
2017
4
DE
2018
4
DE
2019
3
DE
2020
3
CH
2001
2
CH
2002
1
CH
2003
1
CH
2004
2
CH
2005
5
CH
2006
4
CH
2007
1
CH
2008
4
CH
2009
2
CH
2010
3
CH
2011
2
CH
2012
2
CH
2013
1
CH
2014
1
CH
2015
3
CH
2016
1
CH
2017
4
CH
2018
3
CH
2019
4
CH
2020
3
IT
2001
3
IT
2002
5
IT
2003
1
IT
2004
5
IT
2005
4
IT
2006
5
IT
2007
5
IT
2008
1
IT
2009
1
IT
2010
4
IT
2011
2
IT
2012
4
IT
2013
3
IT
2014
5
IT
2015
4
IT
2016
2
IT
2017
3
IT
2018
3
IT
2019
3
IT
2020
2
ES
2001
2
ES
2002
1
ES
2003
2
ES
2004
4
ES
2005
1
ES
2006
1
ES
2007
4
ES
2008
1
ES
2009
1
ES
2010
2
ES
2011
2
ES
2012
1
ES
2013
2
ES
2014
1
ES
2015
5
ES
2016
4
ES
2017
5
ES
2018
4
ES
2019
1
ES
2020
2