How to read the band →
Solid line = floor (spellings that unambiguously belong to the group). Shaded band up to the dashed edge = ceiling (the most it could reach if every ambiguous spelling counted here).
Heaven
Heaven is now well below its former popularity. All-time it's been given to 30,804 U.S. babies, the 918th most common name by sound today, peaking at 1,370 in 2006, with 569 in 2025.
Heaven has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).