Sales Year Ended December 31 2020 % Change 2019 % Change 2018 Sales by Product Group Disability and Group Life and AD&D Group Long-term Disability $ 239.7  (0.7) % $ 241.5  (0.9) % $ 243.8  Group Short-term Disability 158.7  (0.3) 159.2  14.8  138.7  Group Life and AD&D 224.3  (13.2) 258.3  (8.5) 282.4  Subtotal 622.7  (5.5) 659.0  (0.9) 664.9  Supplemental and Voluntary Individual Disability 71.4  (5.9) 75.9  (1.7) 77.2  Voluntary Benefits 241.6  (19.6) 300.6  (0.8) 303.1  Dental and Vision 63.9  (14.3) 74.6  7.5  69.4  Subtotal 376.9  (16.4) 451.1  0.3  449.7  Total Sales $ 999.6  (10.0) $ 1,110.1  (0.4) $ 1,114.6  Sales by Market Sector Group Disability and Group Life and AD&D Core Market (< 2,000 employees) $ 377.0  1.7  % $ 370.8  (6.2) % $ 395.1  Large Case Market 245.7  (14.7) 288.2  6.8  269.8  Subtotal 622.7  (5.5) 659.0  (0.9) 664.9  Supplemental and Voluntary 376.9  (16.4) 451.1  0.3  449.7  Total Sales $ 999.6  (10.0) $ 1,110.1  (0.4) $ 1,114.6  (in millions of dollars) Year Ended December 31, 2020 Compared with Year Ended December 31, 2019 Group sales increased in the core market, which we define as employee groups with fewer than 2,000 employees, compared to 2019 due to growth in our medical stop-loss product, partially offset by lower sales to new and existing customers in our group disability and group life products. Group sales declined in the large case market compared to 2019 due to lower sales to new and existing customers in all products. The sales mix in the group market sector for 2020 was approximately 6 1 percent core market and 39 percent larg e case market. Individual disability sales, which are primarily concentrated in the multi-life market, decreased compared to 2019 due to lower sales to both new and existing customers. Voluntary benefits sales decreased compared to 2019, driven by lower new and existing customer sales in both the core and large case markets. Dental and vision sales decreased compared to 2019 driven by lower sales to both new and existing customers. We believe the lower sales levels during 2020 compared to 2019 are driven by the impact of COVID-19, which has caused higher unemployment levels and general uncertainty around the financial condition of our customers as well as disruption in our sales processes. Further discussion of COVID-19 is contained herein in "Executive Summary" in this Item 7. Year Ended December 31, 2019 Compared with Year Ended December 31, 2018 Group sales declined slightly compared to 2018 due to lower new customer sales in both the core market and large case markets, partially offset by higher sales to existing customers in both the core and large case markets and growth in our medical stop-loss product. The sales mix in the group market sector for 2019 was approximately 56 percent core market and 44 percent large case market. Individual disability sales decreased compared to 2018 due to lower sales to new customers. Voluntary benefits sales decreased slightly compared to 2018, primarily driven by lower sales to new customers in the core market, partially offset by higher sales 70