Popularity in the United States (by decade)
Numbers
| Kay (feminine) | Kay (masculine) | |||||
| Year | Rank | Percent Used | Rank | Percent Used | ||
| 2020 | - | - | - | - | ||
| 2010 | - | - | - | - | ||
| 2000 | - | - | - | - | ||
| 1990 | #1741 | 0.004 | - | - | ||
| 1980 | #1070 | 0.008 | - | - | ||
| 1970 | #642 | 0.015 | - | - | ||
| 1960 | #250 | 0.066 | - | - | ||
| 1950 | #149 | 0.125 | #1358 | 0.002 | ||
| 1940 | #98 | 0.219 | #765 | 0.005 | ||
| 1930 | #136 | 0.157 | #505 | 0.012 | ||
| 1920 | #416 | 0.021 | #748 | 0.007 | ||
| 1910 | #374 | 0.026 | #1039 | 0.004 | ||
| 1900 | #505 | 0.015 | #1258 | 0.003 | ||
| 1890 | #915 | 0.005 | #1415 | 0.001 | ||
| 1880 | #1134 | 0.002 | #1343 | 0.001 | ||
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