I have the following population pyramid:

This was created using the following code (and inspired by How can I draw this population pyramid graph with pgfplots?):
\usepackage[top=1cm,bottom=1cm,left=1cm,right=1.5cm,headsep=10pt,a5paper]{geometry}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=1.5}
\usepackage{pgfplotstable}
\pgfplotsset{%
compat=1.9,
blank onypyramid axis style/.style={%
width=.4\textwidth,
height=.9\textheight,
scale only axis,
grid=both,
grid style={line width=.1pt, draw=gray!10},
major grid style={line width=.2pt,draw=gray!50},
xmin=0,
ymin=-0.5,
ymax=100,
y dir=reverse,
enlarge y limits={value=0.075,upper},
xbar,
axis x line=left,
xtick align=outside,
bar width=1,
allow reversal of rel axis cs=false,
},
onypyramid axis style/.style={%
blank onypyramid axis style,
ytick=\empty,
axis line style={-},
},
}
\begin{document}
\noindent
\begin{center}
\begin{tikzpicture}
\pgfplotstableread[
col sep=comma,
header=true,
]{
age,man,woman
+100,3239,17739
99,1467,6747
98,2077,8821
97,3300,13147
96,5521,20072
95,10678,36223
94,17900,57028
93,23710,70410
92,30627,84807
91,39280,101469
90,50093,121123
89,62308,139512
88,74389,155204
87,86637,169994
86,99516,184102
85,114880,201392
84,130166,216864
83,141785,225710
82,152126,231591
81,161716,235885
80,171579,241231
79,179663,243912
78,188631,247329
77,196180,249705
76,205013,254313
75,208232,250901
74,204536,238733
73,214654,246486
72,238030,270074
71,253235,284824
70,262680,292425
69,307252,339968
68,361831,396704
67,379329,412652
66,386101,419454
65,391717,424872
64,389501,421755
63,387421,419341
62,390482,421381
61,391805,422810
60,396961,428105
59,400338,430518
58,405035,433262
57,409054,434856
56,415554,438940
55,422521,443250
54,424667,444135
53,425314,443401
52,431730,448371
51,442007,457258
50,444324,456418
49,444199,453080
48,441831,447687
47,441362,444478
46,448893,449314
45,458370,454899
44,467723,461910
43,473540,464424
42,467762,455789
41,447908,435953
40,420141,408975
39,399557,388749
38,397863,386465
37,401311,389476
36,403744,391584
35,419248,406252
34,429618,416015
33,426746,412514
32,411021,397746
31,400932,388252
30,406783,393343
29,411780,397362
28,410855,397171
27,409331,394917
26,406501,392629
25,408614,392446
24,411935,394785
23,408055,390608
22,396293,379224
21,388067,371710
20,393484,376693
19,400651,382432
18,401069,381452
17,402381,382647
16,407070,387255
15,416278,396183
14,422145,402840
13,417960,399408
12,414913,396523
11,415819,397032
10,418482,399165
9,424928,405826
8,427231,408023
7,426182,407592
6,427303,408799
5,428335,409615
4,429337,410454
3,427512,408338
2,425369,406276
1,423220,404203
0,421272,402313
}\loadedtable
\pgfplotstablecreatecol[
expr accum={
round(\pgfmathaccuma) + \thisrow{man} + \thisrow{woman}
}{0}
]{sum}{\loadedtable}
\tikzset{
fpu=true,
}
\pgfplotstablegetrowsof{\loadedtable}
\pgfmathsetmacro{\LastRow}{\pgfplotsretval-1}
\pgfplotstablegetelem{20}{sum}\of{\loadedtable}
\pgfmathsetmacro{\Sum}{\pgfplotsretval}
\tikzset{
fpu=false,
}
\begin{axis}[
onypyramid axis style,
axis y line*=left,
ytick={0,5,...,100},
yticklabels={},
ytick style={draw=none},
grid=both,
grid style={line width=.1pt, draw=gray!10},
major grid style={line width=.2pt,draw=gray!50},
name=popaxis,
]
\addplot [magenta,fill=magenta!50] table [
y expr =\coordindex,x expr={\thisrow{woman}},
] \loadedtable;
\node [anchor=south] at (rel axis cs:0.25,1)
{\textcolor{magenta}{Woman}};
\end{axis}
\begin{axis}[
onypyramid axis style,
at={(popaxis.west)},
anchor=east,
xshift=-12.5mm,
x dir=reverse,
every node near coord/.append style={
anchor=east,
},
axis y line*=right,
]
\addplot [cyan,fill=cyan!50] table [
y expr =\coordindex, x expr={\thisrow{man}},
] \loadedtable;
\node [anchor=south] at (rel axis cs:0.25,1)
{\textcolor{cyan}{Man}};
\end{axis}
\begin{axis}[
blank onypyramid axis style,
at={(popaxis.west)},
anchor=east,
xshift=-12.5mm,
x dir=reverse,
axis y line*=right,
xtick=\empty,
ytick={0,5,...,100},,
yticklabels={100+,95,90,...,0},
y tick label style={
align=center,
inner sep=0pt,
text width=12.5mm,
},
major tick length=0pt,
axis line style={
-,
draw=none,
},
]
\addplot [draw=none,fill=none] table [
y expr =\coordindex, x expr={0},
] \loadedtable;
\end{axis}
\end{tikzpicture}
\end{center}
Question 1 : I would like to add two axis on the right and left of the pyramid with a year indication every five years (see example in the image below). Is this feasible? If so, can anybody provide some help?
Question 2 : If I wanted to add numbers to point at some feature of the pyramid (as shown in the second image), how could I proceed?

