The last five years have been marked by a continuous, state-by-state assault on abortion rights. In that time, abortion rates have plummeted.

Tying those two facts together may be beneficial to backers of the pernicious, often constitutionally questionable laws meant to limit access to abortion to the point of a de facto ban. But it doesn’t hold up to serious scrutiny.

Instead, falling abortion rates are in large part the result of affordable, effective contraception, which itself is the result of the broader affordability of health insurance. If the goal is fewer abortions, then clearly the path is through better access to the best methods of birth control.

The numbers bear this out. According to a survey of 45 states by The Associated Press, the abortion rate decreased nationwide by 12 percent from 2011 to 2014 or 2013, depending on the latest data available from each state. (Maine’s rate also fell 12 percent.)

Also during this time, a total of 267 abortion restrictions were enacted in 31 states, according to the Guttmacher Institute, a research group that supports abortion rights.

These laws — from required waiting times and doctor visit thresholds to forced ultrasounds and costly and unnecessary clinic standards — contributed to the closing of about 70 clinics across a dozen states, including 27 in Texas and 12 each in Michigan and Arizona.

However, there was no connection between a state’s level of restrictions and its number of abortions.

In fact, according to an analysis at FiveThirtyEight, five of the six states with the biggest declines in abortion rate have passed no recent laws to restrict access.

The only two states to see a significant increase in abortion rate, though, were the aforementioned Michigan, as well as Louisiana, recently selected No. 1 by Americans United for Life for reducing access to abortion. (Both increases are attributed in part to women coming from nearby states.)

More likely causing the drop were the changes in the teenage pregnancy rate, which has been falling since the early 1990s, and the overall birth rate, which hit a record low in 2013.

Indeed, the use of highly effective birth control methods, such as intrauterine devices and hormonal implants, has been rising in recent years, hitting an all-time high in 2014.

IUDs are 45 times more effective than oral contraceptives and 90 times more effective than male condoms in preventing pregnancy, but they are expensive.

Under the Affordable Care Act, however, contraceptives must be covered with no copay, putting these methods within the reach of poor women, the most likely demographic to get an abortion.

Simply put, women are getting fewer abortions because the women most likely to get an abortion are getting pregnant less often.

Abortion restrictions may be forcing women to drive farther to find a clinic, or to delay the procedure until they have the money and time off from work, They are certainly a rallying cry for far-right conservatives.

But it is improved access to contraception that is accomplishing the one goal shared by both sides of this very contentious issue.