It's hard to have hard stats on this but this would depend on the level of morality in society. In a completely virtuous society, likely close to 100%. In a corrupt society that embraces perverted values like hedonism, likely close to 1%.
With the intention? There is way too many factors here, so a lot of assumptions will have to be made in order to vote on this. I voted 1%-50% because women, on average, ovulate for about 1 week per month, which equals out to about 1/4th of their entire reproductive life (puberty-menopause). So the probability of getting pregnant at any given time (assuming 100% conception rate if intercourse happens during ovulation) is around 25% if neither partner has any idea where the woman is in her cycle. If the couple is trying to conceive, they most likely take note of when the woman is ovulating. They will increase their instances of intercourse from their norm, and will have a 100% occurrence of "intent to conceive". People not is stable relationships do not have sex as often as people who do, but have an extremely high instance of "intent to not conceive". So, high instance of 100% intent to conceive vs a relatively low instance of high percentage of "intent to NOT conceive" would put it in the 1-50% range.
1) The poll question and answers were NO what I wanted. The filter made me change it over-and-over. I though it was having issues with "intercourse", but I think it is making answers things like < 1%. Regardless, the question still works, just not worded as I wanted either the question or answers.
I have a hard time believing even the 3 (1 to 50) votes. If you take a somewhat average man or woman @ ~112 instances of intercourse per year its VERY hard to believe that intent was to conceive more than .9%
@Krampus - I don't disagree. What I was trying to gauge was obvious, but difficult in a simple one question poll. Every instance of sex is not an invitation (intent) to conceive. I am 45, and have NO idea how many times I have had sex. I will just use the average I found (it sounds reasonable) of ~112/year. I started having sex @17, that is over 3,000 instances. I have ONE child, and still have NEVER set out to conceive.