Figure 4.
The bar chart presents type of contribution counts by year from 2004 to 2025. Conceptual counts are 1 in 2004, 1 in 2006, 1 in 2007, 1 in 2010, 1 in 2012, 2 in 2014, 2 in 2015, 3 in 2016, 2 in 2017, 2 in 2018, 1 in 2019, 1 in 2020, 3 in 2021, 2 in 2022, and 1 in 2023. Empirical counts are 1 in 2009, 2 in 2011, 1 in 2012, 2 in 2014, 2 in 2015, 3 in 2016, 3 in 2017, 5 in 2018, 6 in 2019, 4 in 2020, 4 in 2021, 4 in 2022, 3 in 2023, 13 in 2024, and 1 in 2025. The empirical trend line increases more steeply than the conceptual trend line.Type of contribution