The most reliable source of crime stats in the USA is the FBI, which aggregates all the data from state, county and local police forces. Not all such data is reported to the FBI on a daily basis, and once the data is in it takes the FBI time to collect, analyze it and properly report it ... so you're never going to be able to get stats for the current year in the current year.

But generally speaking, over the past decade the number of women over age 18 who die of homicide each year has been around 3,200. Plus 300-400 girls under 18.

The FBI released a preliminary report of crime stats for 2019 in late January of this year, but it only includes January-June 2019. I haven't looked at it closely so I don't know if the prelim report breaks down homicide data by sex. Personally, I usually don't bother with the preliminary half-year results. But here's the link to the prelim Jan-June 2019 report:

https://ucr.fbi.gov/crime-in-the-u.s/2019/preliminary-report/home

2018 is the most recent year for which the FBI has reported stats for the entire year. In 2018, 3,180 women in the US age 18 and above died of homicide; 341 girls under age 18.

By contrast, 10,914 males age 18 and above; 784 boys under 18. In addition in 2018 there were 29 homicide victims in the US over 18 and one under 18 whose sex wasn't reported for some other reason is listed as "unknown."

On a daily and weekly basis, 8.7 females were killed by homicide per day in the US in 2018, 61 a week; and 29.9 males died of homicide each day, 209 per week.

https://ucr.fbi.gov/crime-in-the-u.s/2018/crime-in-the-u.s.-2018/topic-pages/tables/expanded-homicide-data-table-1.xls

https://ucr.fbi.gov/crime-in-the-u.s/2018/crime-in-the-u.s.-2018/topic-pages/expanded-homicide

Given what 2020 has been like, I imagine the numbers for the current year will be higher.

In the UK, the best source is the Office of National Statistics, aka the ONS.