Popularity in the United States (by decade)
Numbers
| Willis (masculine) | Willis (feminine) | |||||
| Year | Rank | Percent Used | Rank | Percent Used | ||
| 2020 | - | - | - | - | ||
| 2010 | - | - | - | - | ||
| 2000 | #1755 | 0.004 | - | - | ||
| 1990 | #1003 | 0.006 | - | - | ||
| 1980 | #649 | 0.010 | - | - | ||
| 1970 | #548 | 0.013 | - | - | ||
| 1960 | #456 | 0.016 | - | - | ||
| 1950 | #345 | 0.022 | - | - | ||
| 1940 | #238 | 0.041 | - | - | ||
| 1930 | #173 | 0.075 | #1878 | 0.002 | ||
| 1920 | #142 | 0.103 | #1741 | 0.002 | ||
| 1910 | #138 | 0.106 | #1763 | 0.002 | ||
| 1900 | #146 | 0.100 | - | - | ||
| 1890 | #123 | 0.108 | - | - | ||
| 1880 | #106 | 0.118 | - | - | ||
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