2011 - 18.9%

The 2011 18.9% is the baseline measurement.

2012 - 21.5%

The 2012 increase to 21.5% from 2011 represents a 2.6% increase YoY.

2013 - 20.8%

The 2013 decrease to 20.8% from 2012 represents a -0.7% decrease YoY.

2014 - 20.1%

The 2014 decrease to 20.1% from 2013 represents a -0.7% decrease YoY.

2015 - 18.3%

The 2015 decrease to 18.3% from 2014 represents a -1.8% decrease YoY.

2016 - 18%

The 2016 decrease to 18% from 2015 represents a -0.3% decrease YoY.

2017 - 16.7%

The 2017 decrease to 16.7% from 2016 represents a -1.3% decrease YoY.

2018 - 16.9%

The 2018 increase to 16.9% from 2017 represents a 0.2% increase YoY.

2019 - 15.5%

The 2019 decrease to 15.5% from 2018 represents a -1.4% decrease YoY.

2021 - 14.2%

The 2021 decrease to 14.2% from 2019 represents a -1.3% decrease YoY.

2022 - 15.1%

The 2022 increase to 15.1% from 2021 represents a 0.9% increase YoY.

2023 - 15.2%

The 2023 increase to 15.2% from 2022 represents a 0.1% increase YoY.