Popularity in the United States (by decade)
Numbers
| Cassidy (feminine) | Cassidy (masculine) | |||||
| Year | Rank | Percent Used | Rank | Percent Used | ||
| 2020 | #459 | 0.038 | - | - | ||
| 2010 | #277 | 0.059 | - | - | ||
| 2000 | #164 | 0.104 | - | - | ||
| 1990 | #153 | 0.105 | #1236 | 0.004 | ||
| 1980 | #589 | 0.018 | #861 | 0.006 | ||
| 1970 | #1832 | 0.003 | #1514 | 0.002 | ||
| 1960 | - | - | - | - | ||
| 1950 | - | - | - | - | ||
| 1940 | - | - | - | - | ||
| 1930 | - | - | - | - | ||
| 1920 | - | - | - | - | ||
| 1910 | - | - | - | - | ||
| 1900 | - | - | - | - | ||
| 1890 | - | - | - | - | ||
| 1880 | - | - | - | - | ||
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