(IDEX Online) - Walmart, Costco, Amazon, Macy's and JC Penney account for almost half the fine jewelry and watch sales made by north America's 10 biggest supersellers.The combined sales totals from membership-only warehouse clubs, hypermarkets, department stores and general e-commerce were 8.1bn in 2019, according to the newly-published State of the Majors report by National Jeweler magazine.By comparison, market leader Signet and four other majors with jewelry as their sole or primary business sold a combined total of $9.9bn.Signet - whose empire includes Kay Jewelers, Zales and Jared - remains by far the dominant jeweler with its $5.56bn sales more than doubles those of second-placed Walmart.It also has vastly more outlets than any other chain - 2,757 compared with second-placed Swarovski (325) and The Kroger Co (242).National Jeweler compiled data on all 38 fine watch and jewelry retailers with sales over $100m.Signet's sales were down marginally on 2018 - $5.56bn compared with $5.64bn. Third-placed Tiffany saw a small increase in sales but the biggest rise of all among the top 10 was Amazon, up 17 per cent from $1.34bn to $1.622bn. Top 10 sales of fine jewelry and watches in North America 2019 (with 2018 figures) 1. Signet $5.56bn ($5.64bn)2. Walmart $2.71bn ($2.75bn)3. Tiffany $1.65bn ($1.62bn) 4. Costco $1.62bn ($1.65bn) 5. Amazon $1.62bn ($1.34bn)6. Richemont $1.56bn ($1.54bn)7. Macy's $1.49bn ($1.48bn)8. JC Penney $641m ($652m)9. Jewelry Television $611m ($571m)10. Bucherer $561m ($555m)Figures compiled by National Jeweler for sales in USA, Canada, Mexico and Caribbean are based on the company's most recently completed fiscal year