Segment Outlook to new customers in the large case market. Dental and vision sales increased compared to 2018 driven by higher sales to both new and existing customers. We remain committed to offering consumers a broad set of financial protection benefit products at the worksite. During 2021, we will continue to invest in a unique customer experience defined by simplicity, empathy, and deep industry expertise through the re-design of our processes and the increased utilization of digital capabilities and technology to enhance enrollment, underwriting, and claims processing. In addition, we will continue to focus on the expansion of our portfolio of products. In particular, with respect to smaller employers, we will continue to provide comprehensive consumer-focused products, enhance our distribution model, and utilize our MyUnum platform and digital tools to bring industry leading enrollment capabilities and a fully integrated customer experience. Our differentiated offering with HR Connect and significant investment in leave management services will allow for substantial growth opportunities, particularly with larger employers, and stronger persistency in our core products. We believe our active client management and differentiated integrated customer experience across our product lines, underpinned by strong risk management, will continue to enable us to grow our market over the long-term. Given the uncertainty caused by the COVID-19 pandemic, we expect to experience further disruption in our sales activity and ultimately premium income in 2021, particularly in the first half of the year. We could also continue to experience claims volatility, particularly in our short-term disability and group and voluntary life products as well as potential disruption in our overall claims processing activity which can result in short-term unfavorable experience. In addition, we could continue to experience an increase in the volume of activity associated with our leave management product which would lead to an increase in expenses. The low interest rate environment continues to place pressure on our profit margins by impacting net investment income yields as well as potentially discount rates on our insurance liabilities. Our net investment income may continue to be unfavorably impacted by fluctuations in miscellaneous investment income. As part of our continued pricing discipline and our reserving methodology, we continuously monitor emerging interest rate experience and adjust our pricing and reserve discount rates, as appropriate. We continuously monitor key indicators to assess our risks and adjust our business plans accordingly. 71