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After the most unpopular second term of the post-World War II era, George W. Bush has gained in public esteem as time since his presidency has passed - not that the public's ready yet to throw him bouquets.

Just more than four years after he left office, with his presidential library about to open its doors, Americans divide on Bush's performance during his tumultuous eight years as president: Forty-seven percent approve while 50 percent disapprove in a new ABC News/Washington Post poll.

See PDF with full results, charts and tables here.

Albeit tepid, that score represents progress for Bush. His overall approval rating is 14 percentage points higher now than at the end of his second term; approval for his handling of the economy is 19 points higher, and he's gained, although more slightly, on the Iraq war as well.

It's not unusual for a former president to advance in public esteem after he's left the fray of partisan politics, but neither is it guaranteed. In polls four to five years after the end of their presidencies, Bush's father gained 18 points in approval, but Bill Clinton slipped by 4 and Ronald Reagan lost 12. (Reagan later improved in retrospect; it just took more time.)

Bush left office with just 33 percent approval, and a disapproval rating, 66 percent, that tied the disgraced Richard Nixon as the highest on record for a departing president in polls since the Roosevelt administration. Bush's approval rating on average across his second-term, for its part, stands alone as the lowest on record in modern polling.

With his improvements since returning to Texas, Bush remains negatively rated on two central issues of his presidency, but more narrowly so than when he was in office. The public by 53-43 percent disapproves of his handling of the economy, compared with 73-24 percent in late 2008. And this poll, produced for ABC by Langer Research Associates, finds that Americans by 57-40 percent disapprove of his decision to invade Iraq. That compares with a 65-33 percent negative rating for his handling the situation there in mid-2008.

GROUPS - Bush's gains in approval are fairly broadly based, albeit still with sharp partisan and ideological gaps. His approval rating is up by 19 points among Democrats compared with when he left office, as well as by 16 points among Republicans and 11 points among independents. Still, though, just 25 percent Democrats now approve of his performance (it was a mere 6 percent when he left), as do 45 percent of independents and 84 percent of Republicans.

Bush's rating has gained 10 points among liberals and 15 points among moderates, as well as 12 points among his core conservative supporters, albeit again with big gaps; just 21 percent of liberals approve, rising to 43 percent of moderates and 69 percent of conservatives.

Notably, there are three key groups among which Bush's improvement has barely budged: Blacks, among whom his approval rating has gained 7 points, to just 15 percent; young adults (age 18 to 29), up 8 points to 34 percent; and middle- to upper-middle income Americans, in the $50,000-$100,000 bracket, up 9 points to 48 percent approval for the former president. The first two are not statistically significant changes; the third is, slightly so.

Finally, there's another way in which Bush's ratings have mellowed. Intensity of opinion about his presidency was remarkably negative as he left office in January 2009; 51 percent of Americans "strongly" disapproved of his work in office, while just 16 percent approved strongly. Intensity of sentiment remains negative today, but less lopsidedly so - 34 percent have a strongly negative view of his presidency, down 17 points, while 20 percent strongly approve.

Check here for a full retrospective of public attitudes on Bush across his presidency.

METHODOLOGY - This ABC News/Washington Post poll was conducted by landline and cell phone April 17-21, 2013, in English and Spanish, among a random national sample of 1,000 adults. Results have a margin of sampling error of 3.5 points. The survey was produced for ABC News by Langer Research Associates of New York, N.Y., with sampling, data collection and tabulation by SSRS/Social Science Research Solutions of Media, Pa.