Haak is on the verge of doing the almost "impossible": To hit with better than 50.0% in a single season in Serie A1. She has 50,2% atm this season. I have only recgonized Egonu, Soucy and Betcheva to accomplish this feat or pass that milestone in the past 30 years. Both Artamonova and Sokolova were very close to achive it, but they failed at the finishing line.
Here are the most impressive seasons - in terms of efficiency among OH/OPPs with at least 10 games and 250 attack points - during the last 30 years I am able to detect:
Egonu, Paola, 58,8%, in 2020/2021
Egonu, Paola, Italy, 54,4%, in 2019/2020
Soucy Brigitte, Canada, 51,2% in 1997/1998
Egonu, Paola, Italy, 51,2% in 2021/2022
Betcheva, Teodora, Bulgaria, 50,2% in 1997/1998
Artamonova/Estes, Evgenjia, Russia, 49,7% in 2000/2001
Biamonte, Daniela, Italy, 49.5% in 1997/1998
Sokolova, Liubov, Russia, 49,2% in 2002/2003
Glinka, Malgorzata, Poland, 48,4% in 2003/2004
Haak, Isabelle, Sweden, 48,3% in 2022/2023
Francia, Mirka, 48,2% in 2006/2007
Phipps, Keba, USA, 48,1% in 1997/1998
Francia, Mirka, Cuba, 48,0% in 2005/2006
Sokolova, Liubov Russia, 47,8% in 2003/2004
Skowronska, Katia, Poland, 47,6% in 2008/2009
Togut, Elisa, Italy, 47,6% in 2006/2007
Gray, Alexa, Canada, 47,1% in 2019/2020
Zetova, Antonia, Bulgaria, 47,1% in 2000/2001
Egonu, Paola, Italy, 46,9% in 2017/2018
Glinka, Malgorzata, Poland, 46,9% in 2001/2002
Weersing Henriette, Netherlands, 46,8% in 1997/1998
Egonu, Paola, Italy, 46,6% in 2018/2019
Zetova, Antonia, Bulgaria, 46,3% in 1999/2000
Rinieri, Simona, Italy, 46,3% in 2004/2005
Phipps, Keba, USA, 46,3% in 1999/2000
Gray, Alexa, Canada, 46,1% in 2020/2021
Francia, Mirka, Cuba, 46,1% in 2004/2005
Jelic, Barbara, Croatia, 45,8% in 1999/2000
Crawford, Therese, USA, 45,8% in 2000/2001
Piccinini, Fransesca, Italy, 45,7% in 2005/2006
Togut, Elisa, Italy, 45,7% in 2004/2005
Aguero, Taismary, Italy, 45,6% in 2006/2007
Gray, Alexa, Canada, 45,4% in 2021/2022
Beccaria, Vania, Italy, 45,4% in 2000/2001
Turlea, Carmen, Romania, 45,4% in 2001/2002
Aguero, Taismary, Italy, 45,3% in 2001/2002
Menchova, 45,0% in 2002/2003
Togut, Elisa, Italy, 45,0% in 2000/2001
Rinieri, Simona, Italy, 45,0% in 2000/2001
Roll, Sylvia, Germany, 44,9% in 2001/2002
Plummer, Katheryn, USA, 44,7% in 2022/2023
Fabris, Samantha, USA, 44,7% in 2017/2018
Hill, Kimberley, USA, 44,0% in 2018/2019
Grun, Angelina, Germany, 44,0% in 2002/2003
Antropova, Ekaterina, Italy, 43,6% in 2022/2023
Ting, Zhu, China, 43,1% in 2022/2023