Year to Date Count Distinct (Cumulative)

I already managed to obtain a cumulative distinct count by months but I can't get it when trying to do it by years (YTD Count Distinct with partition between diferente years). I tried partition function but I keep getting all kinds of errors, this is what I got so far. Could you give me some guidance, Im new at this.

create table table2 (id serial, fecha_captura date, mn integer, VALUACION1 integer);

insert into table2 (fecha_captura, mn, VALUACION1)
values
('1996-02-01',2,12345),
('1996-02-01',2,12345),
('1996-02-01',2,12344),
('1996-02-01',2,12343),
('1996-03-01',3,12345),
('1996-03-01',3,12346),
('1996-03-01',3,12347),
('1996-03-01',3,12348),
('1996-04-01',4,12349),
('1996-04-01',4,12350),
('1996-04-01',4,12351),
('1996-04-01',4,12352),
('1997-03-01',4,12353),
('1997-03-01',4,12354),
('1997-03-01',4,12345),
('1997-03-01',4,12352),
('1997-04-01',4,12353),
('1997-04-01',4,12354),
('1997-04-01',4,12345),
('1997-04-01',4,12355);

SELECT Year1,mn,
COUNT(DISTINCT(VALUACION1)) AS Val_Dist_Mes
,SUM(flag) AS Val_Dist_Mes_Nuevas
,SUM(SUM(flag))
OVER (partition by Year1 ORDER BY mn,Year1
ROWS UNBOUNDED PRECEDING) AS Val_Dist_Acum
FROM
(
SELECT
VALUACION1
,EXTRACT(MONTH FROM fecha_captura) AS mn
,EXTRACT(YEAR FROM fecha_captura) AS Year1
,CASE
WHEN EXTRACT(MONTH FROM fecha_captura)
= MIN (EXTRACT(MONTH FROM fecha_captura))
OVER (PARTITION BY VALUACION1)
THEN 1
ELSE 0
END AS flag
FROM table2
GROUP BY fecha_captura,VALUACION1
) AS dt
GROUP BY mn,Year1

[Results][2]:

| year1 | mn | val_dist_mes | val_dist_mes_nuevas | val_dist_acum |

| 1996 | 2 | 3 | 3 | 3 |
| 1996 | 3 | 4 | 3 | 6 |
| 1996 | 4 | 4 | 3 | 9 |
| 1997 | 3 | 4 | 3 | 3 |
| 1997 | 4 | 4 | 1 | 4 |

[EXPECTED RESULTS][2]:

| year1 | mn | val_dist_mes | val_dist_mes_nuevas | val_dist_acum |

| 1996 | 2 | 3 | 3 | 3 |
| 1996 | 3 | 4 | 3 | 6 |
| 1996 | 4 | 4 | 4 | 10 |
| 1997 | 3 | 4 | 4 | 4 |
| 1997 | 4 | 4 | 1 | 5 |

EXTRACT() is not a T-SQL function, you are not using Microsoft SQL Server ?

try changing the inner most query to

SELECT VALUACION1, 
       EXTRACT(MONTH FROM fecha_captura) AS mn, 
       EXTRACT(YEAR FROM fecha_captura) AS Year1, 
       CASE 
		WHEN EXTRACT(MONTH FROM fecha_captura) 
                =    MIN(EXTRACT(MONTH FROM fecha_captura)) OVER (PARTITION BY VALUACION1,
                                                                               EXTRACT(YEAR FROM fecha_captura))
		THEN 1
		ELSE 0
		END AS flag
FROM table2
GROUP BY fecha_captura, VALUACION1